NIST Technical Note 1909

2011 Wildland Urban Interface 

Amarillo Fires Report #2 – Assessment 

of Fire Behavior and WUI 

Measurement Science 

Alexander Maranghides

Derek McNamara

http://dx.doi.org/10.6028/NIST.TN.1909
NIST Technical Note 1909

2011 Wildland Urban Interface 

Amarillo Fires Report #2 – Assessment 

of Fire Behavior and WUI 

Measurement Science 

Alexander Maranghides 

Fire Research Division 

Engineering Laboratory

Derek McNamara

Geospatial Measurement Solutions, LLC

Hood River, OR 

This publication is available free of charge from: 

http://dx.doi.org/10.6028/NIST.TN.1909

February 2016

U.S. Department of Commerce

Penny Pritzker, Secretary

National Institute of Standards and Technology

Willie May, Under Secretary of Commerce for Standards and Technology and Director
Certain commercial entities, equipment, or materials may be identified in this

document in order to describe an experimental procedure or concept adequately. Such

identification is not intended to imply recommendation or endorsement by the

National Institute of Standards and Technology, nor is it intended to imply that the

entities, materials, or equipment are necessarily the best available for the purpose. 

In accordance with the Metric Conversion Act of 1975 as amended by Section 5164 of the Omnibus Trade 

and Competitiveness Act of 1988 and as required by related provisions of the Code of Federal Regulations, 

the National Institute of Standards and Technology (NIST) uses the modern metric system of measurement 

units (International System of Units; abbreviation: SI) in all publications. When the field of application or 

the special needs of users of NIST publications require the use of non-SI units, the values of quantities are 

first stated in SI units and the corresponding values expressed in non-SI units follow in parentheses.

National Institute of Standards and Technology Technical Note 1909

Natl. Inst. Stand. Technol. Technical Note 1909, 153 pages (February 2016) 

Coden: NTNOEF

This publication is available free of charge from: 

http://dx.doi.org/10.6028/NIST.ITN.1909

Cover Page Figure: Fire direction, fire road crossings, and general fire progression in 

Timber Creek Canyon. Prevailing wind direction at time of fire was from the Southwest
ii

Table of Contents

Table of Contents.............................................................................................................. ii

List of Tables.................................................................................................................... iv

List of Figures................................................................................................................... vi

Abstract.............................................................................................................................. x

Executive Summary......................................................................................................... xi

1.0 Introduction................................................................................................................. 1

2.0 Report Objectives, Goals & Organization................................................................ 4

3.0 Materials and Methods............................................................................................... 5

3.1 Data Sources ......................................................................................................... 5

3.2 Field Data Enhancement and Local Data Integration ........................................... 6

3.3 Fire Witness Accounts, Images and Radio Logs.................................................. 8

3.4 Fire Timeline Development ................................................................................ 10

3.5 Topography and Radar........................................................................................ 11

4.0 Study Area, Weather and Event Overview ............................................................ 12

4.1 Study Area .......................................................................................................... 12

4.2 Weather Summary .............................................................................................. 12

4.3 Timeline Overview ............................................................................................. 13

5.0 Timber Creek Canyon Community ........................................................................ 17

5.1 Damage Assessment, Fire Direction, Fire Timeline and Burned Vegetation..... 17

5.2 Defensive Action Categorizations ...................................................................... 19

5.3 Topographic Information.................................................................................... 19

5.4 Structural Element Ignition Mechanisms............................................................ 20

5.5 Vegetative Element Ignition Mechanisms.......................................................... 28

6.0 Plateau........................................................................................................................ 33

6.1 Damage Assessment, Fire Direction and Fire Timeline ..................................... 33

6.2 Defensive Action Categorizations ...................................................................... 34

6.3 Topographic Information.................................................................................... 34

6.4 Vegetation Element Ignition Mechanisms.......................................................... 34

7.0 Palisades South.......................................................................................................... 42

7.1 Damage Assessment, Fire Direction and Fire Timeline ..................................... 42

7.2 Fire Behavior ...................................................................................................... 44

7.3 Defensive Action Categorizations ...................................................................... 45

7.4 Topographic Information.................................................................................... 46

7.5 Structural Element Ignition Mechanisms............................................................ 46

7.6 Vegetative Element Ignition Mechanisms.......................................................... 60

8.0 Palisades North and Tangle Aire............................................................................. 61

8.1 Damage Assessment, Fire Direction and Fire Timeline ..................................... 61

8.2 Fire Behavior ...................................................................................................... 63

8.3 Defensive Action Categorizations ...................................................................... 63

8.4 Topographic Data................................................................................................ 64

8.5 Structural Element Ignition Mechanisms............................................................ 64

8.6 Vegetative Element Ignition Mechanisms.......................................................... 72

9.0 North Lake Tanglewood........................................................................................... 72

9.1 Damage Assessment, Fire Direction and Fire Timeline ..................................... 73

9.2 Fire Behavior ...................................................................................................... 74
iii

9.3 Defensive Action Categorizations ...................................................................... 74

9.4 Topographic Information.................................................................................... 75

9.5 Structural Element Ignition Mechanisms............................................................ 83

9.6 Vegetative Element Ignition Mechanisms.......................................................... 84

10.0 South Lake Tanglewood......................................................................................... 86

10.1 Damage Assessment, Fire Direction and Fire Timeline ................................... 86

10.2 Defensive Action Categorizations .................................................................... 88

10.3 Topographic Information.................................................................................. 88

10.4 Structural and Vegetative Element Ignition Mechanisms ................................ 89

11.0 Southeast Lake Tanglewood .................................................................................. 95

11.1 Damage Assessment, Fire Direction and Fire Timeline ................................... 95

11.2 Defensive Action Categorization...................................................................... 95

11.3 Topographic Information.................................................................................. 96

11.4 Structural and Vegetative Element Ignition Mechanisms. ............................... 96

12.0 WUI Assessment Methodology and Science ....................................................... 102

12.1 Pre-fire Hazard Mitigation Guidance and Assessment................................... 102

12.2 Pre-Fire and Post-Fire Landscaping Characteristics....................................... 103

12.3 Building Characteristics.................................................................................. 105

12.4 Topographic Characteristics ........................................................................... 106

12.5 Defensive Actions and Fire Behavior............................................................. 107

12.6 Fire Weather.................................................................................................... 109

12.7 Exposure Characterization.............................................................................. 109

13.0 Technical Findings Summary .............................................................................. 110

14.0 Recommendations................................................................................................. 113

15.0 Conclusions............................................................................................................ 114

16.0 Acknowledgments................................................................................................. 114

Appendix A NIST TN1708 Preliminary Findings ..................................................... 115

Appendix B Unassessed Building Characteristics ..................................................... 117

Appendix C Unconfirmed Defensive Actions............................................................. 120

Appendix D Suggested Improvements to the NIST WUI Assessment Defensive 

Action Methodology...................................................................................................... 122

Appendix E Aspect Transformations.......................................................................... 124

Appendix F Tabulation of Incident Data and Discussion ......................................... 126

Appendix G Recommendations for Improvements to WUI 2 Data Collection System

......................................................................................................................................... 134

Appendix H Example of Pre-Fire WUI Mitigation Advice Form Implemented in 

Areas Affected by the Tanglewood Fire...................................................................... 138

17.0 References.............................................................................................................. 143
iv

List of Tables

Table 1 Imagery used for post-fire assessment................................................................... 7

Table 2 Ancillary electronic data sources used in analysis................................................. 8

Table 3 First responder discussions by departments along with known resources allocated 

by department.............................................................................................................. 9

Table 4 KAMA Weather Data Summary.......................................................................... 13

Table 5 KVII TV Lake Tanglewood Weather Data Summary. ........................................ 14

Table 6 Damage and destruction to detached combustibles in Timber Creek Canyon. .. 18

Table 7 Damage and destruction to linear features in Timber Creek Canyon................. 18

Table 8 Damage and destruction to features in Timber Creek Canyon by defensive 

action......................................................................................................................... 19

Table 9 Damage and destruction to detached combustibles in Plateau Community. ...... 34

Table 10 Damage and destruction to linear features in Plateau Community................... 34

Table 11 Damage and destruction to detached combustibles in Palisades South and 

selected portions of South Lake Tanglewood Community....................................... 42

Table 12 Damage and destruction to linear features in Palisades South and selected 

portions of Lake Tanglewood Community. .............................................................. 43

Table 13 Damage and destruction to features in Southern Palisades and selected portions 

of North Lake Tanglewood categorized by identified defensive actions. ................ 46

Table 14 Damage and destruction to detached combustibles in Palisades North, Tangle 

Aire and selected portions of North Lake Tanglewood Communities. .................... 62

Table 15 Damage and destruction to linear features in Palisades North, Tangle Aire and 

selected portions of North Lake Tanglewood Communities. ................................... 62

Table 16 Damage and destruction to features in Northern Palisades, Tangle Aire and 

selected portions of North Lake Tanglewood categorized by identified defensive 

actions. ...................................................................................................................... 64

Table 17 Damage and destruction to detached combustibles in North Lake Tanglewood 

Community. .............................................................................................................. 73

Table 18 Damage and destruction to detached linear features in North Lake Tanglewood 

Community. .............................................................................................................. 74

Table 19 Damage and destruction to features in North Lake Tanglewood Community 

categorized by identified defensive actions. ............................................................. 75

Table 20 Damage and destruction to detached combustibles in South Lake Tanglewood 

Community. .............................................................................................................. 87

Table 21 Damage and destruction to linear features in South Lake Tanglewood 

Community. .............................................................................................................. 88

Table 22 Damage and destruction to features in South Lake Tanglewood Community 

categorized by identified defensive actions. ............................................................. 88

Table 23 Damage and destruction to detached combustibles in Southeast Lake 

Tanglewood............................................................................................................... 95

Table 24 Damage and destruction to linear features in Southeast Lake Tanglewood 

Community. .............................................................................................................. 95

Table 25 Damage and destruction to features in Southeast Lake Tanglewood Community 

categorized by identified defensive actions. ............................................................. 96

Table 26 Damaged structures with damage status and defensive action. ....................... 107

Table 27 Eave Material across Residential Structures................................................... 118
v

Table 28 Eave Type across Residential Structures........................................................ 118

Table 29 Gutter Material across Residential Structures ................................................ 118

Table 30 Roof and Gutter Debris across Residential Structures.................................... 119

Table 31 Shutter Material across Residential Structures............................................... 119

Table 32 Window Frame Type across Residential Structures....................................... 119

Table 33 Window Pane Type across Residential Structures ......................................... 119

Table 34 Anecdotal Defensive Actions ......................................................................... 121

Table 35 Issues and possible corrections with defensive action data collection 

methodology. .......................................................................................................... 123

Table 36 Damage status of residential structures by structure type............................... 128

Table 37 Damage status of residential structures by exterior type. ................................ 128

Table 38 Damage status of residential structures by roof type....................................... 129

Table 39 Damage status of residential structures by foundation type (NIST/TFS)........ 129

Table 40 Damage status of residential structures by foundation type (Potter-Randall 

County). .................................................................................................................. 129

Table 41 Damage status of residential structures by chimney presence......................... 129

Table 42 Damage status of residential structures by mean aspect (5m ((16.4 ft)) radar 

derived) within 9.1 m (30 ft) around the structure.................................................. 130

Table 43 Damage status of residential structures by mean aspect (5m ((16.4 ft)) radar 

derived) within 30.5 m (100 ft) around the structure.............................................. 130

Table 44 Damage status of residential structures by mean aspect (5m ((16.4 ft)) radar 

derived) within 61.0 m (200 ft) around the structure.............................................. 130

Table 45 Damage status of residential structures by mean aspect (5m ((16.4 ft)) radar 

derived) within 91.4 m (300 ft) around the structure.............................................. 131

Table 46 Damage status of residential structures by mean slope (5m ((16.4 ft)) radar 

derived) within 9.1 m (30 ft) around the structure.................................................. 131

Table 47 Damage status of residential structures by mean slope (5m ((16.4 ft)) radar 

derived) within 30.5 m (100 ft) around the structure.............................................. 131

Table 48 Damage status of residential structures by mean slope (5m ((16.4 ft)) radar 

derived) within 61.0 m (200 ft) around the structure.............................................. 131

Table 49 Damage status of residential structures by mean slope (5m ((16.4 ft)) radar 

derived) within 91.4 m (300 ft) around the structure.............................................. 132
vi

List of Figures

Figure 1 Overview of WUI Assessment Methodology used here. ..................................... 3

Figure 2 General procedures used in this report on the Tanglewood Fire. Pre-season 

training and property level data collection methods are described in NIST TN 1708.

..................................................................................................................................... 6

Figure 3 Fire affected communities showing number of structures and percent destroyed 

by community. .......................................................................................................... 15

Figure 4 General Timeline and fire direction observations generalized from radio logs, 

fire images, and post-fire data collection.................................................................. 16

Figure 5 Damage to structural elements in Timber Creek Canyon. ................................. 21

Figure 6 Fire direction, fire road crossings, and general fire progression in Timber Creek 

Canyon. Prevailing wind direction at time of fire was from the Southwest. ........... 22

Figure 7 Specific time observations and general fire behavior in Timber Creek Canyon.23

Figure 8 Defensive action areas and primary structure categorizations in Timber Creek 

Canyon. Larger structures shown in imagery and not categorized to a defensive 

action status are secondary buildings and not residential. ........................................ 24

Figure 9 Radar derived percent slope in Timber Creek Canyon. ..................................... 25

Figure 10 Radar derived aspect in Timber Creek Canyon................................................ 26

Figure 11 Ignition mechanisms in and around 411 Roberts Drive, close to the fire origin. 

Structure was defended. ............................................................................................ 29

Figure 12 Ignition mechanisms around non-damaged or non-destroyed residential 

structures in Timber Creek Canyon, NIST photos.................................................... 30

Figure 13 Structural element ignition mechanisms at 338 Cactus Drive. Structural 

elements portrayed are known or suspected to be ignited prior to residential structure 

ignition. Fire direction was from southeast to northwest and the attached fence was 

on the north of the destroyed home, NIST photos.................................................... 31

Figure 14 Pre-fire and post-fire imagery showing how vegetation treatments or landuse 

might have effected fire behavior. Approximate fire line is shown in red on image 

to the right................................................................................................................. 32

Figure 15 Damage to structural elements in the Plateau Community. ............................. 35

Figure 16 Fire direction and fire timeline in Plateau Community. All times are on 

2/27/2011. ................................................................................................................. 36

Figure 17 Plateau area defensive action locations and primary structure categorizations in 

the Plateau Community............................................................................................. 37

Figure 18 Radar derived percent slope in Plateau area..................................................... 38

Figure 19 Radar derived aspect in Plateau Community.................................................... 39

Figure 20 Treated vegetation around 209 Quail Ridge Road that might have helped to 

stop fire from contacting house. Exact contributions of defensive actions are 

unknown.................................................................................................................... 40

Figure 21 Two distinct vegetation ignitions adjacent to structure at 209 Quail Ridge 

Road. Red feature is 15 cm (6 in) long ballpoint pen, NIST photos........................ 41

Figure 22 Damage to structural elements in the southern Palisades Community and 

selected portions of the South Lake Tanglewood Community................................. 47

Figure 23 Fire direction in Southern Palisades and South Lake Tanglewood Community. 

The main fire front moved through area between 14:30 and 15:30 on 2/27/2011. .. 48
vii

Figure 24 Palisades South and portions of South Lake Tanglewood with specific time 

observations on 2/27/2011. ....................................................................................... 49

Figure 25 General fire behavior observations and location of retardant drop in southern 

Palisades community and portions of South Lake Tanglewood............................... 50

Figure 26 Post-fire south facing oblique imagery showing results of higher intensity fire 

on the southeastern side (northeast facing) of the canyon ........................................ 51

Figure 27 Post-fire south facing oblique imagery showing results of fire behavior in the 

upper portion of the middle canyon area of Southern Palisades Community........... 52

Figure 28 Post-fire east facing oblique imagery showing results of fire behavior in the 

bottom of the middle canyon area of Southern Palisades Community..................... 53

Figure 29 Post-fire south facing oblique imagery showing results of fire behavior in the 

eastern most canyon area of the Southern Palisades and South Lake Tanglewood 

Communities............................................................................................................. 54

Figure 30 Defensive action locations and primary structure categorizations in Southern 

Palisades and selected areas of South Lake Tanglewood Communities................... 55

Figure 31 Radar derived percent slope in Palisades South and selected portions of South 

Lake Tanglewood Communities............................................................................... 56

Figure 32 Radar derived aspect in Palisades South and selected portions of South Lake 

Tanglewood Communities........................................................................................ 57

Figure 33 Burned hay bales leading from destroyed secondary structure to primary 

structure causing scorching on the brick siding. Categorization of defensive actions 

is unknown, NIST photo. .......................................................................................... 58

Figure 34 Unidentified burned features adjacent to the northern side of the residential 

structure at 102 Gary Drive. These features are believed to be ignited by the burning 

mobile home to the north of the brick residential structure, NIST photo. ................ 59

Figure 35 A: Stand replacing fire in the canyon to the west of 102 Gary Drive. B: 

Vegetation and building features with minimal damage at the top of the canyon, 

indicating topographically influenced fire behavior. Image taken from the south side 

of 102 Gary Drive looking north, NIST photos........................................................ 60

Figure 36 Portions of the fire perimeter overlaid on pre-fire (2009) color-infrared 

imagery. Fire did not travel into redder residential grass areas. This could be due to 

exposure conditions, defensive actions, pre-fire vegetation treatment or a 

combination of these factors. .................................................................................... 61

Figure 37 Damage to structural elements in the northern Palisades, Tangle Aire and 

selected portions of North Lake Tanglewood Communities. ................................... 65

Figure 38 Fire direction and fire timeline in north Palisades, Tangle Aire and selected 

portions North Lake Tanglewood Communities. The main fire front moved through 

this area between 15:00 and 15:30 on 2/27/2011. A wind shift occurred later on 

2/27/2011 that caused flare-ups and fire direction from the north. The second fire 

front, portrayed as an orange arrow above, was observed as one fire direction 

indicator in the field observed through radiant heat damage and confirmed through 

eyewitness observations............................................................................................ 66

Figure 39 Palisades North, Tangle Aire and portions of North Lake Tanglewood specific 

time observations on 2/27/2011 from radio logs and images. 114 Palisades 

Boulevard was destroyed late in the night of 2/27/2011 or in the early morning hours 

of 2/28/2011 after a wind shift from the north occurred. It is believed all other 

destroyed structures burned before 17:00 on 2/27/2011........................................... 67
viii

Figure 40 Fire behavior observations in Palisades North, Tangle Aire and portions of 

Lake Tanglewood North communities...................................................................... 68

Figure 41 Defensive action locations and primary structure categorizations in Northern 

Palisades, Tangle Aire and selected areas of North Lake Tanglewood Communities.

................................................................................................................................... 69

Figure 42 Radar derived percent slope in Northern Palisades, Tangle Aire and selected 

areas of North Lake Tanglewood Communities. ...................................................... 70

Figure 43 Radar derived aspect in Northern Palisades, Tangle Aire and selected areas of 

North Lake Tanglewood Communities..................................................................... 71

Figure 44 Ignited deck, which was extinguished by homeowners, NIST photo. ............. 72

Figure 45 Fully involved residential structure at 128 Exmoor Road igniting residential 

structure at 130 Exmoor Road, Photo Gordon Ivy, used by permission................... 72

Figure 46 Field delineated burned vegetation around Tangle Aire Point overlayed on a 

false color composite pre-fire image. Red areas show healthy photosynthetically 

active vegetation. ...................................................................................................... 73

Figure 47 Damage to structural elements in the North Lake Tanglewood Community... 76

Figure 48 Fire direction and fire timeline in North Lake Tanglewood Community. The 

main fire front moved through the area between 15:00 and 18:30 on 2/27/2011..... 77

Figure 49 North Lake Tanglewood specific time observations on 2/27/2011 from radio 

logs and images......................................................................................................... 78

Figure 50 Fire behavior changes coincident with topography. Side directly exposed to 

wind (left) saw limited scorching and no torching of trees in post-fire imagery, and a 

low intensity ground fire during Amarillo Sheriff Helicopter flight. Side not facing 

wind (right) exhibited scorching and torching of trees in post-fire imagery, and a 

high intensity crown fire during helicopter flight was observed. ............................. 79

Figure 51 Defensive action locations and primary structure categorizations in North Lake 

Tanglewood Community. ......................................................................................... 80

Figure 52 Radar derived percent slope in North Lake Tanglewood Community............. 81

Figure 53 Radar derived aspect in North Lake Tanglewood Community. ....................... 82

Figure 54 Partially destroyed fence at 100 Camino Alto, NIST photo............................. 83

Figure 55 Defended firewood pile at 100 Camino Alto, NIST photo. ............................. 83

Figure 56 Damaged wooden bench and burned and unburned vegetation on west side of 

100 Camino Alto, NIST photo.................................................................................. 84

Figure 57 Partially destroyed wood fence, which caused scorching to brick siding and 

melting of vinyl soffit, NIST photo. ......................................................................... 84

Figure 58 Burnt hedgerow and Buffalo grass that facilitated fire spread to destroyed 

secondary structure at 105 Port-O-Call Drive, NIST photo. .................................... 85

Figure 59 Pre-fire false color imagery showing redder areas that did not burn along with 

brown to black areas that did burn. In some locations the fire perimeter ended where 

these red, photosynthetically active, areas began and interior, red, photosynthetically 

active areas did not burn. .......................................................................................... 86

Figure 60 Damaged pergola roof ignited by embers, NIST photo. .................................. 89

Figure 61 Damage to structural elements in the South Lake Tanglewood Community... 90

Figure 62 Fire direction and fire timeline in South Lake Tanglewood Community. ...... 91

Figure 63 Defensive action locations and primary structure categorizations in South Lake 

Tanglewood Community. ......................................................................................... 92

Figure 64 Radar derived percent slope in South Lake Tanglewood Community............. 93
ix

Figure 65 Radar derived aspect in South Lake Tanglewood Community. ....................... 94

Figure 66 Damage to structural elements in the Southeast Lake Tanglewood Community.

................................................................................................................................... 97

Figure 67 Fire direction in Southeast Lake Tanglewood Community. The main fire front 

moved through area by 18:21 on 2/27/2011 based on Amarillo Sheriff Helicopter 

flight.......................................................................................................................... 98

Figure 68 Southeast Lake Tanglewood Community defensive action locations and 

primary structure categorizations.............................................................................. 99

Figure 69 Radar derived percent slope in Southeast Lake Tanglewood Community..... 100

Figure 70 Radar derived aspect in Southeast Lake Tanglewood Community................ 101

Figure 71 A: Image of burned vegetation right after the main fire front moved through the 

area.......................................................................................................................... 104

Figure 72 Residential structures by appraised building values and by damage status. .. 127

Figure 73 Residential structures by effective year built and by damage status.............. 128

Figure 74 Erroneous field collected burn vegetation boundary...................................... 136
x

Abstract

On February 27, 2011, three fires began in the outskirts of Amarillo, Texas, two of which 

destroyed or damaged buildings in multiple housing developments. The National 

Institute of Standards and Technology (NIST), as part of its Disaster and Failure Studies 

Program, began gathering electronic data for the incident within 6 hours of the 

Tanglewood fire front moving through the Palisades Community in Lake Tanglewood. 

NIST and the Texas Forest Service (TFS) integrated a field data collection team into the 

Incident Command System (ICS) within 48 hours to conduct a post-fire assessment. 

Initially, both the Willow Creek South Complex and Tanglewood Complex fires were 

assessed. Within 72 hours after ICS integration, the Tanglewood Fire became the focus 

of the deployment. The deployment also supported local and state damage assessment 

efforts. 

This assessment represented the first deployment of the NIST Wildland Urban Interface 

(WUI) 2 field data collection method where logistics and standard operating procedures 

(SOPs) were integrated into the ICS. Information was collected in the field related to 

residential structures, combustible features, non-combustible features, fire direction, fire 

timeline, burned vegetation and defensive actions. Documentation included over 29 000 

ground photographs, 2330 geolocated man-made features, 281 distinct records of burned 

vegetation, and discussions with 48 first responders and homeowners. Pre-fire and postfire aerial imagery as well as radar data were acquired for the study area. All of the data 

collected was entered into a Geographic Information System (GIS) database, which is 

being prepared for public dissemination.

This report represents the second report for the Tanglewood Complex Fire. The first 

report, NIST Technical Note 1708, provided information on all three fires and provided 

an overview of possible technical factors affecting the damage, failure, and/or successful 

performance of buildings and/or infrastructure in the aftermath of the fire. The first

summary report addressed the particulars of the deployment. Additionally, the first

report provided a summary of the primary structures lost. 

This second report provides the event timeline reconstruction and general fire behavior 

observations. Additionally, a general assessment of defensive actions is presented to 

show the spatial extent of these actions and identify potential structure and parcel level 

ignition mechanisms. Topographic characteristics within the affected communities are 

discussed. This report also details structural and vegetative element ignition mechanisms 

throughout the communities affected by the Tanglewood Fire. A discussion of current 

WUI mitigation information is conducted in the context of applicable hazard mitigation 

for the affected communities and an assessment of WUI fire measurement science is 

presented. 

KEY WORDS: Amarillo fires, community fires, fire data collection, fire behavior, 

Tanglewood Fire, Wildland Urban Interface, WUI, WUI data collection 
xi

Executive Summary

On February 27, 2011, three fires  the Willow Creek Complex, the Tanglewood 

Complex, and the Country Club  began on the outskirts of Amarillo, Texas. The

Tanglewood Complex fire was the main focus of this case study. Out of the 183 buildings 

exposed, 35 structures were destroyed and 13 were damaged in multiple housing 

developments. The National Institute of Standards and Technology (NIST), as part of its 

Disaster and Failure Studies Program, began gathering data for the incident within 6 

hours of the Tanglewood fire front moving through the Palisades Community in Lake 

Tanglewood. NIST and the Texas Forest Service (TFS) integrated a field data collection 

team into the Incident Command System (ICS) within 48 hours to conduct a post-fire 

assessment. Initially, both the Willow Creek South Complex and Tanglewood Complex 

fires were assessed. Within 72 hours after ICS integration, due to resource limitations, 

the Tanglewood Fire became the focus of the deployment. The deployment also 

supported local and state damage assessment efforts. 

NIST has developed a two tiered approach, documented in NIST Technical Note 1708, to 

enable the collection of reliable Wildland Urban Interface (WUI) fire data. The first tier, 

called WUI 1, was used to collect general data across the entire perimeter of the 

Tanglewood Complex fire, while the second tier, WUI 2, was used to collect in-depth fire 

behavior, timeline, defensive action and structural performance data.

This assessment was the first deployment of the NIST WUI 2 field data collection 

method where logistics and standard operating procedures (SOPs) were integrated into 

the ICS. Information was collected in the field related to residential structures, 

combustible features, non-combustible features, fire direction, fire timeline, burned 

vegetation and defensive actions. Documentation included over 29 000 ground 

photographs, 2330 geolocated man-made features, 281 distinct records of burned 

vegetation and discussions with 48 first responders and homeowners. Pre-fire and postfire aerial imagery as well as radar data were acquired for the study area. All of the data 

collected was entered into a Geographic Information System (GIS) database, which is 

being prepared for public dissemination. 

This is the second report about the Tanglewood Complex Fire. The first report provided 

information on all three fires and provided an overview of possible technical factors 

affecting the damage, failure, and/or successful performance of buildings and/or 

infrastructure in the aftermath of the fire. The first summary report, NIST TN 1708, 

provided a summary of the primary structures lost. 

This second report provides the event timeline reconstruction and general fire behavior 

observations. Additionally, a general assessment of defensive actions is presented to 

show the spatial extent of these actions and identify potential ignition mechanisms. Out 

of the 183 structures in the study domain 82 (45%) were identified as having been 

defended during the fire.

Topographic characteristics within the affected communities are discussed. This report 

also details structural and vegetative element ignition mechanisms throughout the 

communities affected by the Tanglewood Fire. A discussion of current WUI mitigation 

information is conducted in the context of applicable hazard mitigation for the affected 

communities and an assessment of WUI measurement science is presented. 
xii

It has been found that the lack of evidence of a defensive action around a particular 

structure or feature does not mean that a defensive action did not occur on that feature.

Additionally defended damaged structures, in many cases, did not show direct signs of 

defensive actions. Without the evidence and comprehensive documentation of defensive 

actions, the field observations can be wrongly interpreted as self-extinguishment.

Relatively recent technologies like automated vehicle location (AVL) systems, mobile 

phones, global positioning systems (GPS) and imaging technologies like GoProTM allow 

recording of real time fire information to better understand fire timeline information. 

Many features including fences and railroad ties (landscaping timbers) were recorded as 

being defended multiple times by different first responders highlighting the features’ long 

lasting potential to generate flames and embers, therefore increasing the hazard to nearby 

unburned structures. 

In examining the ignition of residential structures, it was found that secondary structures

if ignited can, expose primary residences under certain conditions to increased hazardous 

conditions. Secondary structures are frequently not addressed in hazard mitigation 

guidance. It was also found that embers and fire generating combustibles, both detached 

and attached, included fences, decks, railroad ties (used as landscaping timbers), mulch 

beds, attached stairs and piles of firewood. Detached combustibles, in numerous cases, 

ignited prior to the primary structure and resulted in the ignition of the primary structure. 

In numerous cases, defensive actions prevented structure ignition of primary and 

secondary structures.

The post-fire scene represents the final product of the interactions among exposure, 

defensive actions and the response of fuels (vegetative or urban) to the actual received 

exposure. The exposure itself is a function of fuels, topography and the local weather. It 

was found that the exposure, defensive action and weather can vary with time. There can 

be numerous fire fronts, wind shifts and multiple defensive actions all taking place at 

different times. The exposure from a fire burning up to or near a structure varied 

significantly throughout the incident. In some cases, a very low intensity fire reached the 

structure walls while in other cases very severe exposure was experienced by the 

structure without fuel reaching all the way to the structure walls. In numerous locations, 

steep slopes or cliffs appeared to stop fire spread in both the upward and downward 

direction. It should be noted that fire direction observations from the field should not be 

interpreted without utilizing a detailed event timeline, as multiple fire fronts or changes in 

wind direction can occur during the fire incident. 

A number of technical findings were identified with respect to data collection and 

analysis. The complexities of collecting field data with sufficient temporal and spatial 

resolution make the quantification of exposure in the post-fire environment extremely 

difficult to complete. There can be, however, great value in a qualitative assessment of 

exposure as this information can be used, in first order, to determine how the event 

developed and which homes were exposed to significant fire and embers, and which 

homes were not. This report shows that the information collected from detailed post-fire 

case studies is more useful for assessing hazard mitigation technology failures than for

quantifying successes.
xiii

The timely collection of aerial imagery was identified as a significant data collection 

issue, with data being lost with time. Additionally, it was determined that wildlands and 

residential vegetation data is critical to characterizing fire behavior through the WUI 

community. 

It was also determined that remote sensing data collection combined with field 

assessments presents the best means to obtain pre-fire and post-fire vegetation 

information. It should be noted that, even if aerial imagery is collected early, ground 

based imagery still has to be collected. This is necessary as aerial imagery lacks the 

ability to identify understory conditions for both pre-fire and post-fire conditions, and 

even Light Detection and Ranging (LiDAR) data will vary in its ability to identify 

understory conditions. 

In looking at specific building attributes (such as siding type or eaves construction), it 

was confirmed that analysis of structural treatments is possible only when reliable prefire information exists. The availability of pre-fire data is very incident/community 

specific and affects what can be investigated at each incident. This was also identified at 

the Witch/Guejito case study. Additionally, it was determined that many structure 

treatmentsacould be confounding. For example, the destruction of a home with a wood 

roof does not mean the wood roof was the cause of the destruction. Without eyewitness 

accounts of the exposure and subsequent destruction it is impossible to determine the 

ignition sequence.

The Tanglewood Complex post-fire data collection and analysis resulted in a number of 

technical findings, including seven on structure ignition and hazard mitigation, five on 

defensive actions, eight on exposure and fire behavior, and fourteen on data collection 

and analysis methodologies. The technical findings identified in this case study are 

applicable at the interface of wildland and urban areas. The data collection and analysis 

findings will also apply at the Wildland Urban Intermixb.

The five primary findings are listed here:

1. Information collected from detailed post-fire case studies is more useful for assessing

hazard mitigation technology failures than for quantifying successes (data collection 

and analysis methodologies).

2. Damaged structures provided more useful information compared to destroyed 

structures, as building materials and ignition location were more reliably identified

(structure ignition and hazard mitigation).

3. Damaged structures, which were defended, in many cases did not show direct signs of 

defensive actions. Without the collection of defensive action data, the effectiveness of 

hazard treatments can be wrongly interpreted (defensive actions).

 

a Such as, but not limited to roof and siding coverings.

b The term wildland-urban intermix refers to a specific type of wildland-urban interface in 

which the homes or other structures are intermixed with wildland fuels, as opposed to a 

distinct area of wildland fuel adjacent to a developed area.
xiv

4. Remote sensing combined with field assessments presents the best means to obtain 

pre-fire and post-fire vegetation information (data collection and analysis 

methodologies).

5. Mapping of existing hazards in WUI communities without the use of weighted 

attributescprovides a means for identification of existing hazards (manmade and 

natural). This will provide potential for removal of hazards by homeowners and land 

managers, and recognition by first responders during fires (structure ignition and 

hazard mitigation).

The specific findings on structure ignition and hazard mitigation areas include: 

1. Out of the 183 structures documented in this case study, 35 homes were destroyed, 

and 13 were damaged.

2. Secondary structures such as sheds, garages, etc., when ignited, generated a 

significant amount of embers, exposing primary residences under certain conditions

to increased hazardous conditions.

3. Mapping of existing hazards in WUI communities without the use of weighted 

attributes provides a means of identification of existing hazards (manmade and 

natural), thereby providing potential for removal of hazards by homeowners and land 

managers, and recognition by first responders during fires. 

4. Ember and fire generating combustibles, both detached and attached to residential 

structures, include fences, decks, railroad ties, mulch beds, attached stairs and piles of 

firewood.

5. Detached combustibles, in numerous cases, ignited prior to the primary structure and 

were then responsible for the ignition of the structure.

6. Damaged structures, which were defended, in many cases did not show direct signs of 

defensive actions. Without evidence and documentation of defensive action data, the 

effectiveness of hazard treatments can be wrongly interpreted.

7. The exposure from a fire burning up to or near a structure varied significantly across 

the incident. In some cases, a very low intensity fire reached the structure walls, while 

in other cases very severe fire exposure was experienced by the structure even 

without fuel reaching all the way to the structure walls.

The findings on defensive actions include:

8. Out of the 183 structures in the study, 82 (45%) were identified through technical 

discussions as having been defended during the fire.

9. The lack of evidence of a defensive action around a particular structure or feature 

does not mean that a defensive action did not occur on that feature. This implies that 

due diligence in collecting data from first responders is necessary.

10. Same as technical finding #6 (above).

11. Many features including fences and railroad ties were recorded as being defended 

multiple times by different first responders. This is consistent with the features’ long 

 

c Current WUI Fire hazard rating systems rely on very limited technical information to develop weighted 

ratings. Due to this limited technical information such weighed systems can provide erroneous assessments 

of actual hazards.
xv

lasting potential to generate flames and embers. These items increased the hazard to 

nearby unburned structures.

12. Relatively recent technologies such as AVL systems, mobile phones, GPS and 

imaging technologies allow for recording of real time fire information that could help 

better understand fire timeline information. 

The findings on exposure and fire behavior include:

13. Fire moved from the fire origin, in the vicinity of 501 Pinto Drive, and crossed Cactus 

Road into the wildlands to the east of Timber Creek Canyon (a linear distance of 

approximately 500 m (1640 ft.)) in about 30 min or less. 

14. The post-fire scene represents the final product of the interactions between exposure, 

defensive actions and the response of fuels (vegetative or urban) to the actual 

received exposure. This was also identified in the Witch/Guejito case study.

15. Fire and ember exposure onto a target was a complex function of fuels, topography 

and the local weather. The interaction between topography and weather significantly 

affected local exposure conductions. Parcel aspect in combination with local 

prevailing winds sometimes had a significant impact on local exposure conditions.

16. The exposure, defensive actions, and weather vary with time. There were numerous 

fire fronts, wind shifts and multiple defensive actions all taking place at different 

times.

17. Fire burned more intensely along the leeward side of canyons and drainages.

18. Topographic features that significantly affected fire behavior were in many cases less 

than 40 m (130 ft) in length, such as terracing around a structure.

19. In numerous locations, steep slopes or cliffs appeared to stop fire spread in both the 

upward and downward directions. 

20. Fire direction observations from the field were misleading without utilizing a detailed 

event timeline, as multiple fire fronts or changes in wind direction occurred during 

the fire incident. 

The findings on data collection and analysis methodologies include:

21. Electronic data collection systems are essential in capturing the multidimensional data 

and interactions between topography, fuels, weather and defensive actions associated 

with WUI fires. 

22. Same as technical finding #14 (above).

23. Complexities of collecting field data with sufficient temporal and spatial resolution 

make the quantification of exposure in the post-fire environment difficult. There is,

however, great value in a qualitative assessment of exposure as this information can 

be used, in first order, to determine how the event developed and which homes were 

exposed to significant fire and embers and which homes were not. 

24. Information collected from detailed post-fire case studies is more useful for assessing

hazard mitigation technology failures than for quantifying successes. 

25. There is a lack of clear guidance provided to first responders for documenting 

incidents in real time, as well as collecting, sorting and storing incident images and 

video. 

26. Data collected on vegetation both for the wildlands and in the community were

important to understand the fire behavior. 
xvi

27. There is currently no established post-fire data collection methodology to estimate

vegetative fuel consumption. 

28. Remote sensing combined with field assessments presents the best means to obtain 

pre-fire and post-fire vegetation information, as aerial imagery and LiDAR lacks the 

ability to identify understory conditions for both pre-fire and post-fire conditions.

29. Post fire data loss based on aerial imagery increased with time of acquisition after the 

fire. 

30. Analysis of the effectiveness of structure treatments requires pre-fire data for 

comparison. This was also identified during the Witch/Guejito case study, NIST TN 

1635.

31. Many structure treatments could confound the analysis/interpretation of structure 

performance during a WUI fire. For example, the destruction of a home with a wood 

roof does not mean the wood roof was the cause of the destruction. Without 

eyewitness accounts of the destruction, it is impossible to determine the ignition 

sequence.

32. Damaged structures provided more useful information compared to destroyed 

structures, as building materials and ignition location were more reliably identified.

33. There are no case studies similar to this one at the Wildland Urban Intermix, resulting 

in very limited understanding of how to effectively implement mitigation techniques 

in that environment.

34. Currently, there is a no validated physics based fire model capable of providing a 

better understanding of appropriate scales for assessing and analyzing WUI 

environments.

As a result of this study, the following are the five primary technical recommendations:

1. Adequate technologies need to be developed and deployed to document the event 

including first responder actions. - Technical finding #12.

2. The coupling of wind and fire behavior needs to be better characterized, including the 

quantification of wind flow through topographically complex communities. This is 

necessary in order to quantify fire behavior at the WUI - Technical finding #15. 

3. Standardized electronic data collection systems need to be implemented to capture 

post-fire data - Technical finding #21. 

4. Clear guidance need to be developed for first responders to document incidents in real 

time, as well as collect, sort and store incident images and video - Technical finding 

#25. 

5. Pre-fire WUI mitigation advice needs to involve vegetative sampling of wildlands in 

close proximity to residential structures using standardized plot based techniques -

Technical finding #26.

 

Additionally there are three recommendations that will improve community resilience to 

WUI fires by conducting specific research activities as well as data collection. These are:

1. Heat fluxes and ember fluxes from wildland and urban interface fuels need to be 

quantified in both wildfire and controlled environments - Technical finding #3.

2. A methodology needs be developed to estimate vegetative fuel consumption in a postfire environment. Collection of this information should not be limited to residential 

areas and should continue into the wildlands - Technical finding #27.
xvii

3. Case studies similar to this one need be conducted at the Wildland Urban Intermix –

Technical finding #33.
1.0 Introduction

On February 27, 2011, three fires began on the outskirts of Amarillo, Texas, two of 

which destroyed or damaged buildings in multiple housing developments. The National 

Institute of Standards and Technology (NIST), as part of its Disaster and Failure Studies 

Program, began gathering electronic data for the incident within 6 hours of the 

Tanglewood fire front moving through the Palisades Community in Lake Tanglewood. 

NIST and the Texas Forest Service (TFS) integrated a field data collection team into the 

Incident Command System (ICS) within 48 hours to conduct a post-fire assessment. 

Initially, both the Willow Creek South Complex and Tanglewood Complex fires were 

assessed. Within 72 hours after ICS integration, due to resource limitations, the 

Tanglewood Fire became the focus of the deployment. The deployment also supported 

local and state damage assessment efforts. 

NIST has an active program to study the risk to buildings and communities from wildland 

fires. The areas at risk are termed the wildland-urban interface (WUI). NIST has 

statutory authority to deploy teams of technical experts to conduct disaster studies under 

the NIST Organic Act as amended by the America Competes Act of 2010 and the Fire 

Prevention and Control Act of 1974. Findings derived from WUI studies are being 

developed to improve building and landscaping standards, codes, and practices as well as 

improving measurement science associated with the WUI.

Current information regarding the WUI is based on anecdotal information and limited 

assessment of post-fire conditions in the context of the entire fire disturbance continuum.

1

 

Frequently, a structure and its response is only evaluated by looking at the post-fire 

environment without context of fire and ember exposure, local weather, and the potential 

impact of defensive actions. Geographic data sets portraying the basic geographic 

distribution of WUI destruction are limited to coarse scale assessments

2, 3 with no 

significant spatial-temporal database of WUI destruction at the parcel level existing. 

Efforts to categorize wildland fire behavior are in their infancy.

4

 Categorization of fire 

behavior in the WUI is even less developed with only a basic framework currently 

presented on how to proceed with categorization of fire behavior in the wildland and 

WUI.

5

 

The lack of rigorous WUI fire studies is a reflection of the current state of technology 

required for complete assessment of the WUI. The emerging technology is just 

beginning to reach a level of sophistication that is commensurate with the complexities of 

the event. Technology systems that are still being developed and refined for WUI 

applications include remote sensing, heat and ember flux measurements, vegetation 

characterization, unmanned aerial systems, geographical linked information systems

(GIS), and automated vehicle location systems. 

The result has been studies that only examine partial populations,

6

do not assess exposure 

conditions7or do not present details on how exposure conditions and fire timelines were 

determined, but still give recommendations on WUI mitigation advice.

8

 Maranghides et 

al.9categorized the fire timeline, defensive actions and exposure conditions and identified

a limited number of structure and parcel-level fire vulnerabilities for a community 

affected by the 2007 Witch and Guejito fires.
2

Without comprehensive WUI data, extensive post-fire analyses, and science-based 

understanding of the WUI fire phenomena, current WUI mitigation guidance is based on 

anecdotal experience of first responders. First responders provide valuable expert 

knowledge. It is not, however, the responsibility of first responders to scientifically 

assess fire behavior at WUI incidents nor the response of structures to the fire. 

Therefore, and due to the limited perspective any individual first responder can have at 

one incident, development of WUI mitigation guidance based on expert opinion of those 

defending incidents is at best limited and possibly dangerous. As an example, an 

observation may be made that a structure survived the fire assault, with limited 

knowledge of previously conducted defensive actions. 

WUI building codes and standards are also limited by the same lack of data, analyses, 

and science. Current WUI codes and test standards have adapted and extended existing 

design and material performance standards from urban structure-based codes, but the 

testing conditions do not adequately reflect WUI fire conditions. For example, in WUI 

codes and standards such as NFPA 1144,

10 specific separation distances, such as 30 m 

(98 ft) are required to prevent ignition by wildfires. Separation distances or buffer zones 

may be effective in preventing ignition by thermal radiation, but are not effective against 

firebrands, which have been documented to travel 200 m to 300 m (656 ft to 984 ft).

d

 

More effective codes and standards will require better understanding of the underlying 

science of WUI fire phenomena.

There is a need for post-fire assessments to categorize all aspects of the fire incident, 

from pre-fire conditions, through ignition and fire spread, to suppression and post-fire 

recovery (Fire Disturbance Continuum).

1

 NIST has been developing a WUI Assessment 

Methodology to address this need. Through the development of this methodology, NIST

is identifying the measurement science required to categorize all aspects of the fire 

disturbance continuum by attempting to gather data on the following key items:

1. Pre-Fire conditions of the entire WUI environment being studied.

2. Defensive actions that occurred during the fire.

3. Documented evidence of incident time of burning features (e.g. from images

during the fire and local weather conditions).

4. Post-fire assessment of the entire area, focusing on documentation of the entire 

extent of damage and destruction to the wildland and built environments being 

studied and exposed undamaged features being assessed.

In theory, the above data would be used to categorize defensive actions, develop the 

timeline of fire damage and destruction, and quantify fire and ember exposure. 

Collection of the above type of data to divide the respective WUI area into pertinent 

populations of exposure is believed to be an essential step in evaluation of the WUI fire. 

The data is needed to answer questions such as “What structures were exposed to thermal 

flux, flame contact, and firebrands, and when were these populations of structures 

exposed.” This idealized data analysis methodology is presented in Figure 1.

 

d While embers have been documented to travel many kilometers, the majority of both vegetative and 

structural embers is causing ignitions in the first 200 to 300 meters ahead of the wildland fire front or 

burning building. Waldo case study report in progress. 
3

Defensive Actions

Defensive Action CategorizationFire Timeline Development

Radio & GPS Log, Images

Exposure Assessment

Field & Geospatial Data 

Undefended High Exposure Undefended Low Exposure 

Not Defended Ember AssaultNot Defended Main Fire Front

Not Defended Reignitions

Defended High Exposure Defended Low Exposure 

No Exposure 

Figure 1 Overview of WUI Assessment Methodology used here.

The NIST WUI Assessment Methodology also has the advantage of providing a 

framework for guiding conclusions that can be drawn from any WUI assessment. For 

example, the extent to which WUI communities can be subdivided into appropriate 

populations as shown in Figure 1 illustrates the depth and breadth of analyses that can be 

conducted and the conclusions that can be drawn about the respective WUI incident. The 

data available to characterize the fire disturbance continuum will determine the ability to 

partition the respective WUI populations for appropriate analysis, which in turn will 

guide possible analyses that might be conducted; thereby guiding the conclusions that can 

be drawn from any one WUI incident or area. 

It would not, for example, be appropriate to discuss the merits of building retrofit 

techniques when only examining the structures that were not destroyed by the respective 

fire and the characteristics of those non-destroyed (damaged and un-damaged) buildings. 

It would also not be appropriate to study the merits of building retrofitting techniques for 

these same buildings if defensive actions could not be quantified. Finally, assessment of 

building retrofitting techniques for these same buildings would require understanding the 

timeline of fire behavior for the respective incident along with proper, as yet to be 

determined, categorization of wind, fuels and topography as well as a method to integrate 

this data to assess exposure conditions. 

Consequently, NIST is assessing measurement science techniques to determine if 

collection of the above described items is possible in a WUI environment and the 

conditions under which the required data can be collected. This assessment is being 

accomplished through the following activities in post-fire WUI environments:

Data 

Sources

Incident 

Description

Incident 

Analysis
4

1. Implementing a broad and detailed field data collection system as described in 

NIST Technical Note 1708.

11

 

2. Integrating field data with remote sensing data (ground and aerial) to identify fire 

timeline defensive actions, as practical. This activity is performed in a Geographic 

Information System (GIS) environment.

The above activities will also help to identify shortcomings in current measurement 

science techniques; thereby allowing for the potential development of new and improved 

technologies and techniques for assessment of WUI fires. 

The first attempt in assessment and development of the NIST WUI Methodology was at 

the 2007 California Witch Fire as detailed in Maranghides and Mell12 and Maranghides et 

al.

9

 The NIST deployment to the 2011 Texas Tanglewood Fire Complex was 

summarized in Maranghides et al11. The Tanglewood Fire Complex deployment 

conducted a more complete implementation and assessment of the NIST WUI 

Methodology compared to what was conducted for the 2007 California Witch/Guejito

Fire. 

Maranghides et al.

11 detailed deployment procedures, integration of the data collection 

team into the ICS and scope of the data collected for the Tanglewood Fire Complex. 

There were 35 residential structuresedestroyed and 13 damaged residential structures 

found within the perimeter of the Tanglewood Fire. Numerous other secondary 

structures and other combustible features were also damaged or destroyed in the fire. 

Appendix A contains the preliminary findings as identified in Maranghides et al.

11

2.0 Report Objectives, Goals & Organization

This second technical note on the Tanglewood Fire Complex focuses only on the Lake 

Tanglewood Fire. Specifically, this technical note has the goal of assessing current WUI 

post-fire assessment measurement science while providing information to guide 

laboratory experiments and fire model testing and development. Through this 

assessment, we hope to provide a better understanding of fire behavior in the WUI and 

identify potential ignition vulnerabilities. The above goals will be achieved through 

completion of the following objectives related to the 2011 Tanglewood Fire: 

1) Development of the fire event timeline.

2) Documentation of general fire behavior observations. 

3) Documentation of defensive actions.

4) Identification of ignition vulnerabilities. 

All of the above items will be assessed to determine limitations of these items, in terms of 

methods and technologies utilized, regarding achievement of the above described 

objectives. 

 

e Residential structures are those used for residential occupation. This includes guest houses or secondary 

residential structures found on property lots including mobile homes.
5

This fire was selected for a detailed case study after an initial reconnaissance was 

conducted in the first days following the fire. Texas Forest Service had been trained to 

collect WUI data using the NIST methodology, and equipment had been forward 

deployed to Texas in anticipation of a WUI fire. Technically, the Tanglewood Fire

presented a scenario where the impact of topography on fire behavior and structural 

survivability could be analyzed. Additionally, the incident size enabled data collection to 

be conducted for the entire incident, something that was not possible for the 2007 Witch 

fire case study of the Trails community. 

The report is organized beginning with the materials and methods presented in Section 3.

A general overview of the study area and fire timeline is presented in Section 4. In 

sections 5 through 11, the fire area is broken into communities and more detailed fire 

behavior, fire timeline, and ignition mechanisms are detailed. WUI Assessment 

Methodology and Science is discussed in Section 12. Section 13 contains the summary of 

the technical findings. Section 14 contains recommendations and section 15 contains the 

report conclusions. Appendices A through H contain: Preliminary Findings from the 

NIST TN 1708, building materials not assessed, unconfirmed defensive actions, 

suggested data collection defensive action methodology improvements, aspect 

transformations (topographical calculations), tabulation of incident data and discussion, 

recommendations for improving the data collection methodology and an example of prefire mitigation advice form implemented in areas affected by the Tanglewood Fire.

3.0 Materials and Methods

Maranghides et al.

11 detailed the procedures required and outcomes expected for the 

assessment of a WUI fire event. Maranghides et al11 also describes the methods used for 

property level data collection. This property level field data collection occurred on all 

properties in and around the Tanglewood Fire perimeter in February and March of 2011. 

These same procedures were followed for a small number of additional properties 

assessed in a subsequent three day field deployment in August of 2011 in order to 

complete the assessment of all potentially affected properties. Figure 2 portrays the 

training, the property level data collection and additional procedures required to complete 

an assessment of this event.

This section describes the materials and methods used for fire witness data collection and 

office data production. The data sources used for the analysis conducted in this report are 

also detailed. Methods to incorporate these data sources to enhance field collected data 

and create new data are discussed. Finally, the data analysis methods utilized are 

described.

3.1 Data Sources

Table 1 describes aerial imagery used in this analysis. Other ancillary GIS and electronic 

data sources were used for this analysis as shown in Table 2. These electronic data 

sources included images taken during the fire from homeowners and first responders. 

Additionally, sources for weather station information are shown in Table 2. 
6

2) Fire Witness 

Data Collection

3) Office

Data Production

1) Property 

Level 

Data Collection

NIST WUI

Database

Timeline

Reconstruction

Pre-Fire Season Maintenance & 

Training

Analysis & 

Second Report

Defensive

Actions & 

Vulnerabilities

General Fire 

Behavior

Structure 

Response

Figure 2 General procedures used in this report on the Tanglewood Fire. Pre-season training and 

property level data collection methods are described in NIST TN 1708.

3.2 Field Data Enhancement and Local Data Integration 

Geographic Information Systems (GIS) were used for the collection of field data and the 

integration of all data sources. It was determined that electronic data collection systems 

are essential in documenting WUI fires. This is associated with the multidimensionality 

of the data both in space and time, as interactions between topography, fuels, weather and 

defensive actions associated with WUI fires can only be captured in a GIS. The PotterRandall County 911 imagery was used as the base layer from which features were 

recorded in the field in combination with an internal tablet global positioning system 

(GPS), for the majority of the field days. On April 1, 2011 oblique and nadir images 

were acquired by Pictometry, Inc. for the City of Amarillo. The orthorectified imagery 

was used as a new base map from which to more precisely geolocate field collected data 

in the office in order to ensure proper alignment among the different features. This step 

was required due to imprecision in the GPS and improper/erroneous geolocation by data 

collectors. This imagery remained as the base map for all subsequent work. 

Many features in burnt environments were difficult to determine in the field. Pre-fire 

oblique and nadir imagery were compared to post-fire imagery to ascertain changes. 

Footprints of structures were digitized from the post-fire nadir images. Building and 

property characteristics as recorded by the Randall County Assessor web page and shown 

in Table 2 were also entered into the GIS. Nonetheless, in heavily canopied areas certain 

features might have been missed. 
7

Most of the building characteristics recorded in a WUI 2 assessment could not be 

determined for the majority of destroyed homes. Appendix B shows tabulations of these 

building characteristics by residential structure response. There is a disproportionate 

amount of missing values for destroyed homes compared to damaged or undamaged 

homes. This makes further analysis of these building attributes difficult and 

questionable. Consequently, these building treatment values are not assessed further in 

this report. 

Other building characteristics could be obtained for destroyed homes using local tax 

assessor information13. These include exterior siding material, roofing material, flooring, 

roof edge protection and the presence of a chimney. These materials are assessed as 

practical. It was determined that remote sensing combined with field assessments 

presents the best means to obtain pre-fire and post-fire vegetation information.

Table 1 Imagery used for post-fire assessment.

Imagery

Source

Characteristics Acquisition 

Time

Purpose

2008-2009 Texas 

Orthoimagery 

Program

0.5 m (1.6 ft ) spatial 

resolution; two 3-band datasets 

(natural and color infrared).

2008 Leaf On 

Conditions

 Natural color imagery used for first 3 

days of field data collection

 Color infrared used to identify, 

healthy, well-watered vegetation.

2010 National 

Agriculture 

Imagery Program 

(NAIP)

1 m ( 3.3 ft ) spatial resolution 

3-band color infrared.

2010 Leaf On 

Conditions

 Color infrared used to visually 

identify, healthy, well-watered 

vegetation.

Potter-Randall 

County 911 

Imagery

0.3 m (1 ft) spatial resolution 3-

band natural color.

2010 Leaf On 

Conditions

 Imagery used as base data for 

remainder of the first and second 

deployments.

Pre-Fire 

Pictometry

0.15 m (0.5 ft) oblique and 

NADIR 3-band natural color 

imagery.

Pre-Fire 

(Exact Date 

Unknown)

 Verification and identification of prefire conditions.

Post-Fire 

Pictometry

0.15 m (0.5 ft) oblique and 

NADIR 3-band natural color 

imagery.

April 1, 2011  Verification and identification of 

post-fire conditions.

Post-Fire 

Helicopter Video

Color video. 2/27/2011 

18:00-19:00

 Fire timeline reconstruction, fire 

behavior and defensive action 

identification.

Post-Fire Aerial 

Images

Oblique Color Images. 2/28/2012  Verification and identification of 

post-fire conditions.

NextmapTM Basic 

Radar Products

1) Digital Terrain Model 

(DTM) portraying elevation of 

the surface of the bare earth.

2) Digital Surface Model 

(DSM) portraying elevations of 

the surface features.

Unknown  Visual portrayal of topographic 

characteristics. 

 Derivation of slope and aspect.

 Derivation of surface height model.
8

3.3 Fire Witness Accounts, Images and Radio Logs

Technical discussions (TDs) with homeowners and first responders present during the 

Tanglewood Fire were conducted during two field deployments. Each TD was 

documented using hard copy notes, which were subsequently entered into electronic 

format. Locations of defensive actions were also recorded on hard copy maps and 

referenced in the notes. 

Discussions with first responders and homeowners began with a qualitative assessment of 

the resources that were allocated to the Tanglewood Fire. After this assessment, it was 

decided to focus efforts on the fire departments listed in Table 3. Time did not allow for 

discussions with other responders or a quantification of the specific resources allocated.

Additionally, discussions with seven homeowners encountered during various 

deployment activities took place. These discussions included the mayor of the Palisades 

Community and the president of the Lake Tanglewood Homeowners Association. Two 

of the discussions took place with homeowners who conducted their own defensive 

actions on various properties. There was substantial evidence of homeowners not 

Table 2 Ancillary electronic data sources used in analysis.

Data 

Source

Characteristics Time Period Purpose

42

discussions 

with First 

Responders

Hard copy notes and maps 

portraying details of discussions 

with first responders.

Occurred between 

March 1, 2011 

and August 5, 

2011

 Identification of the 

location and characteristics 

of defensive actions.

 General fire chronology.

6 discussions 

with 

homeowners

Hard copy notes and maps 

portraying details of discussions 

with homeowners.

Occurred between 

March 1, 2011 

and August 5, 

2011

 Identification of the 

location and 

characteristics of 

defensive actions.

Assessor 

Web Page

Building characteristics for 

properties in the study area.

Time period of 

data not known

 Identification of building 

characteristics for 

destroyed structures.

911 Radio 

Logs

Printed description of radio 

traffic during the Tanglewood 

Fire.

02/27/2011 11:57

to

02/27/2011 13:40

 Fire timeline creation.

Gordon Ivy

Images -

reporter

Ground images taken during the 

Tanglewood Fire in the Northern 

Palisades Community.

02/27/2011 16:25

to

02/27/2011 17:42

 Fire timeline creation.

Karen Slagle

Images -

resident

Ground images taken during the 

Tanglewood Fire in the Timber 

Creek Community

02/27/2011 16:25

to

02/27/2011 17:42

 Fire timeline creation.

KKTV 

Weather

Weather information from 

weather station located at 

Tanglewood Drive, by the 

entrance of Lake Tanglewood 

community.

2/21/2011 00:00

to

2/28/2011 23:00

 Weather information for 

incident.

Airport 

Weather

Weather information from 

weather station located at the 

Amarillo Airport.

2/26/2011 01:22

to

2/28/2011 23:53

 Weather information for 

incident.
9

evacuating (due to not being aware of the evacuation or the rapidity with which the fire 

spread) and defending their properties. 

Defensive action information from first responder and homeowner hard copy data sheets 

was entered into a GIS database by associating the defensive action with a general 

location represented by a digitized polygon. Within this polygon, if a particular feature 

was identified in the discussion (e.g. railroad ties); this feature was then cross-referenced 

in the database. Defensive actions were recorded in the database; if it was feasible that a 

defensive action might have occurred in the area (e.g. there was fire behavior on or close 

to the location). Additionally, defensive actions evident in videos and images taken 

during the fire and listed in Table 2 were used to confirm defensive actions in certain 

locations. 

Table 3 First responder discussions by departments along with known resources allocated by 

department.

Fire Department Number of 

Discussions

Known Resources Allocated

Lake Tanglewood 

Fire Department

5 First Responders 1 Grass Truck 1900 liters (500 Gallons) of water; 

1 Grass Truck 7600 liters (2000 Gallons) of water; 

1 Grass Truck (unknown capacity); Unknown total 

number of First Responders.

Randall County Fire 

Department

15 First Responders 1 Tanker; 2 Engines 6650 liters (1750 Gallons; 1 

Unknown) of water; 3 Attack Trucks; 1 Brush 

Truck 1900 l liters (500 Gallons) of water; 1 Brush 

Truck (unknown capacity); Vehicle Called 

Command 2; Unknown total number of first 

responders.

Timber Creek Fire 

Department

2 First Responders 1 Brush Truck; 2 Engines; 7 First Responders.

Palisades Fire 

Department

1 First Responder (Fire 

Chief)

Unknown resources.

Amarillo Fire 

Department

23 First Responders Engine 41 (5 First Responders); Training Engine 

50 (4 First Responders); Service Engine 40 (4 First 

Responders); Engine 15 (4 First Responders); 

Engine 5 (4 First Responders); Unit 956 (1 First 

Responder); Unit 952 (1 First Responder).

Happy Fire 

Department

1 First Responder 4WD Rescue 1140 l (300 Gallons) of water.

Pantex Department 1 First Responder 2 Grass Trucks 3800 l (1000 Gallons) of water.

Texas Forest Service 1 First Responder Unknown resources specific to Tanglewood (Total 

resources are known for all three fires but not 

broken down into specific fires).
10

Many defensive actions referenced precise addresses that were often locations where 

there was no fire or associated damage. However, the description often matched that of 

an adjacent or geographically close property and the damage assessed in the field on that 

property. These discrepancies were also noted when a first responder team member 

identified a similar action on a matching property. In these cases, the defensive action 

was associated with the feature that was believed to be defended based on field data and 

multiple anecdotal observations.

Often times there were multiple individuals conducting a defensive action, which was 

also recorded in the database as a single action or set of actions with multiple responders. 

First responders sometimes discussed defensive actions conducted by another first 

responder team. This information was also recorded in the database as the respective 

defensive action being confirmed by multiple observations. Some defensive actions 

could not be associated with a particular action and/or were anecdotal in nature and could 

not be confirmedf. These actions are listed in Appendix C. 

Finally, this cross-referenced defensive action information was used to assign to each 

primary structure a defensive action category as follows:

 Protected: The structure was protected from flames, radiant heat or embers 

produced from fire that was a consequence of the respective wildland fire 

incident.

 Contained: The structure was fully involved or destroyed but the structural fire 

was suppressed to prevent further spread of flames, radiant heat and embers.

 Not Defended: The structure was not defended by any human action during the 

fire incident. Structures in this category would have been specifically identified 

as not defended.

 No Defensive Action identified: There was no defensive action identified on the 

respective structure.

Structures were categorized as described above in an attempt to subdivide or partition the 

study area population into sub-populations for further assessment. The focus of the postfire reconstruction was limited nominally to the first 12 hours after ignition. Defensive 

actions of flare-ups or general mop-up operations that may have occurred after the initial 

fire front were not captured in this data collection. Appendix D lists suggested 

improvements to the NIST Defensive Action Data Collection Methodology. 

3.4 Fire Timeline Development

Information from first responder discussions was also used to re-create the fire timeline. 

Accuracy, however, of first responder time estimates varied greatly and it was often 

difficult to reconcile first responder time estimates with times portrayed in the radio log 

and images. This might have been likely due to the high stress situation that the first 

responders encountered during the incident and the fact that it was not their job to keep 

accurate account of their activities by time. Nonetheless, the first responder accounts did 

 

f Anecdotal defensive actions describing homeowner defensive actions are mapped in the sections below as 

potential locations of defensive actions.
11

help to provide general chronologies of events that were not recorded with images or 

documented in the radio log. 

Fire witness accounts also provide key information in interpretation of actual event 

timelines. For example, the fire in the Timber Creek Community flared up several times 

as was described in discussions by witnesses. Radio logs and images do not provide

sufficient contextual information to help understand and resolve discrepancies in 

timelines. 

The majority of the timeline reconstruction was conducted from the radio logs and fire 

images listed in Table 2. Radio logs provide information of varying accuracy and 

precision. In some cases, the radio log represented the location of the vehicle of the 

responder to the fire, who was actually at a nearby location. An example is the 13 

records in the radio log referencing a conflagration at 415 Palomino Drive. This address 

was outside the fire perimeter but across the street from the fire origin; where many of the 

first responders to the incident parked their vehicles. 

Additionally, many records in the radio log portray a first responder moving from one 

location to another and it was not always clear which of the respective locations, if any, 

had fire. Consequently, radio logs were interpreted in context of other existing data to 

identify what were believed to be reliable burn times. Correlation of these burn times 

with those from images allow for the creation of some aspects of the event timeline. 

3.5 Topography and Radar

The area most affected by the Tanglewood Fire contained unique and distinctive 

topographic features. These features and other topographic characteristics might have 

had consequences for both the fire and ember exposures experienced by structures and 

other combustibles. This is evident at a coarse scale where 34 structures were destroyed 

in the canyon areas around Lake Tanglewood, while only 1 structure was destroyed on 

the plateau above the canyon. The interaction of topography, fuels and weather is 

complex and not well understood. 

Digital elevation models (DEM) portraying elevations of the surface of the earth can be 

valuable in consistently identifying topographic features and characteristics. The 

required scale of topographic analysis, however, is not known for a WUI environment 

and depends on the specific purpose and, possibly, the scale of the features in relation to 

the fire. Initial studies, such as Maranghides et al.

9

, used high resolution data to map high 

hazard areas as a surrogate for exposure. This high resolution data does not exist freely 

for the Tanglewood study area, though other commercial products exist. 

Freely available DEM data is provided by the United States Geologic Survey (USGS). 

This data has a 10 m (33 ft) horizontal resolution. Fire phenomena, particularly structure 

threatening/destroying fire behavior might be occurring on topographic features of finer 

scale than what can be discerned in a coarse scale DEM. This data would be too coarse 

for performing an analysis similar to that performed in Maranghides et al9. 

Resources that were available for this reconstruction were not sufficient to allow for 

acquisition of high resolution DEM products. Radar data at 5 m (17 ft) horizontal spatial 

resolution was available within project resources from NextmapTM. Consequently, this 

report utilizes the radar DEM products to conduct a topographic assessment similar to 
12

that conducted in Maranghides et al.

9 Field collected data identified significant changes 

in fire behavior and exposure occurring over distances much shorter than 5 m (17 ft). 

Percent slope and aspect data sets for all the parcels within the fire perimeter were 

derived from the radar DEM using the ArcGISTM Spatial AnalystTM extension. These 

data sets were used to portray topography in the sections below describing the various 

affected communities. Additionally, the slope and transformed aspect data sets were also 

used to calculate average slopes and aspects within polygons portraying various buffers 

(areas) around residential buildings. 

In order to average aspects within specified polygons, the aspect must be transformed to 

account for the measurement unit being in degrees. The procedures conducted on the 

ArcGIS derived aspect data set can be found in Appendix E. 

4.0 Study Area, Weather and Event Overview

This section provides a brief description of weather at the study area. Additionally, a 

general portrayal of damage by community across the entire study area is presented. 

Finally, a general timeline for the incident is portrayed. Details of each community along 

with the fire timeline and other items are presented in sections below. 

4.1 Study Area 

This study is limited to the area around Lake Tanglewood affected by the fire that 

occurred on February 27, 2011 and continued through February 28. This area is 

comprised of different communities as shown in Figure 3. The Tangle Aire community 

is actually part of the city of Amarillo. The Lake Tanglewood study area has 77 homes, 

the Palisades study area has 71, the Tangle Aire study area has four, the Plateau study 

area has six and the Timber Creek study area has 25 homes. 

These five community groupings provide a convenient method for analyzing different 

areas affected by the Tanglewood Fire. The fire did not stop at community boundaries, 

however, and destruction varied significantly among the different communities. As can 

be seen in Figure 3, Palisades had 77 % (27 of 35), Lake Tanglewood had 20 % (7 of 35) 

and Timber Creek Canyon had 3 % (1 of 35) of the residential structure destructions that 

occurred during the incident.

4.2 Weather Summary

The data provided in this section came from two different sources, the KAMA weather 

station at the Amarillo airport, 21.5 km (13.3 miles) from the fire origin, and the KVIITV weather station, 4.2 km (2.6 miles) in Tanglewood.

g Weather information is 

summarized in Table 4 for the KAMA data and Table 5 for the KVII data. Both weather 

stations recorded very similar weather patterns. There is a 9 m (30 ft) difference in 

elevation between the stations. The KAMA station is surrounded by flat ground and is at 

1099 m (3607 ft) above sea level. The Tanglewood station is 78 m (255 ft) above the 

 

g KVII TV Lake Tanglewood Weather Station- 35:04:20 N, 101:47:35 1 090 m (3 576 ft) elevation 

KAMA 35:13:13 N, 101:43:2 W, 1 099 m (3 607 ft) elevation
13

lake. There were no weather stations down in the canyon and around Lake Tanglewood

(1021 m (3352 ft) elevation), so the potential effects of the topography on the local 

weather cannot be quantified.

Both weather stations provided similar regional weather data. The stations, however, did 

not provide any local weather in the canyons where the Tanglewood Fire burned most 

structures. There was no weather information available within the canyons. Fire behavior 

was observed and field indicators were used to infer wind direction at certain locations, 

however, field data was not available to provide wind speed information.

4.3 Timeline Overview 

The Tanglewood Complex fire ignited in the vicinity of the western intersection of 

Palomino Dr. and Pinto Dr. According to the Randle County Sheriff’s Department, the 

source of ignition remained indeterminate as of April 19, 2011. The Potter-Randal 

County 911 dispatch for the incident was received at 13:44

h

on February 27, 2011; TFS 

dispatch was contacted at 17:56i. Fire suppression activities continued through February 

28.

Figure 4 portrays key time points for the main fire front of the Tanglewood Fire across 

the entire incident. There were numerous flare up and fire direction changes that 

occurred after the fire reached its most northeast extent, where it was extinguished by 

first responders. Wind shifts occurred after the main fire front was extinguished causing 

previously unaffected areas within the fire perimeter to experience fire. Additionally, 

some features within the fire perimeter ignited after the main fire front moved through. 

Table 4 KAMA Weather Data Summary.

Date/ Time

(mm/dd/yyyy hhmm-hhmm)

Weather Observation

02/27/2011 0800-1300  Wind increased from 15 to 66 km/hr (9 to 41 mph)

 RH dropped from 25 to 8 %

02/27/2011 1300-1500

 Sustained wind speed between 57 and 78 km/hr (35 and 48 mph)

 Wind gusting from 83 to 112 km/hr (51 to 69 mph)

 RH between 6 % and 8 %

02/27/2011 1330-2200  Wind from 220° (southwest) and 240° (west southwest)

02/27/2011 2300-2330

 Arrival of weather front

 Wind veered to 350° (north northwest)

 Wind increased from 28 to 41 km/hr (17 to 25 mph)

 RH climbed from 35 % to 65 % 

02/28/2012 0500  Wind dropped under 32 km/hr (20 mph)

 

h Radio Log, Randall County Sheriff Department

i Texas Forest Service Dispatch
14

Table 5 KVII TV Lake Tanglewood Weather Data Summary.

Date/ Time

(mm/dd/yyyy hhmm-hhmm)

Weather Observation

02/27/2011 0800-1300  Wind increased from 1.6 to 44 km/hr (1 to 27 mph)

 RH dropped from 31 % to 6 %

02/27/2011 1300-1500

 Sustained wind speed between 34 and 44 km/hr (21 and 27 mph )

 Wind gusting from 60 to 70 km/hr (37 to 43 mph)

 RH between 6 % and 10 %

02/27/2011 1330-2200  Wind from 225° (southwest) and 245° (west southwest)

02/27/2011 2300-2400

 Arrival of weather front

 Wind veered to 0° (north)

 Wind increased from 20 to 40 km/hr (12 to 24 mph)

 RH climbed from 36 % to 68 % 

02/28/2012 0400  Wind dropped under 32 km/hr (20 mph)
15

Figure 3 Fire affected communities showing number of structures and percent destroyed by community.

Background: City of Amarillo, used by permission, 

overlays NIST
16

Figure 4 General Timeline and fire direction observations generalized from radio logs, fire images, and post-fire data 

collection.

Background: City of Amarillo, 

used by permission, overlays 

NIST
17

5.0 Timber Creek Canyon Community

This section begins with a tabulation of the damage and destruction to structural elements 

in the Timber Creek Canyon Community. Fire timeline, flame heights and fire direction 

information described in this section are derived or estimated from images taken by 

Karen Slagle, radio logs, eyewitness discussions and/or field assessments. 

Additionally, areas where defensive actions were conducted in the community are 

detailed. Topographic characteristics are mapped and discussed. Primary structure 

categorizations to defensive action type are also presented. Finally, a qualitative 

examination of structural and vegetative ignition mechanisms in this community is 

presented. 

5.1 Damage Assessment, Fire Direction, Fire Timeline and Burned 

Vegetation

Figure 5 shows damage to structural elements from the Tanglewood Fire within the 

Timber Creek Canyon Community. As can be seen in Figure 5, there was one primary 

structure with damage to an attached combustible (i.e., wood deck) and one primary 

structure that was completely destroyed, 411 Roberts Road and 338 Cactus Drive, 

respectively. There were 23 primary structures receiving no damage from the fire. 

Damaged combustibles and linear features are, for the most part, concentrated around the 

damaged and destroyed primary structures. 

A breakdown of damage to detached combustible features in Timber Creek Canyon is 

shown in Table 6. Damage and destruction to linear features by length is shown in Table 

7. There is a large length for damaged linear features that is the result of the two long 

fenced areas shown in Figure 5 that could have contributed to ember production and 

possible fire spread. These metal fences with wood posts received minimal damage and 

were not a significant source of radiant heat or embers; one was possibly defended.

Figure 6 shows fire direction and fire progression in Timber Creek Canyon. There were 

six locations where the fire was recorded as crossing a road over seven meters wide based 

on post-fire ground assessments10. The fire also jumped a dirt road (Mesquite Drive) that 

was somewhat narrower than the paved roads. The fire might have jumped more than 

one location in the general area around each fire jump shown in Figure 6. 

Fire moved from the origin and crossed Cactus Road into the wildlands to the east of 

Timber Creek Canyon (a linear distance of approximately 500 m (1640 ft)) in about 

30 minutes or less. North/northwest flanking fires continued to the east of Roberts Drive 

and in the wildlands between Mesquite Drive and Cactus Drive. There was also a 

flanking fire to the west of Roberts Drive. 

The majority of structural element destruction or damaging fire appears to have occurred 

between 13:44 and 16:00 on February 27, 2011. Figure 7 shows specific time 

observations from images and radio logs in Timber Creek Canyon. Additionally, general 

fire behavior is shown in Figure 7. The area around the origin appears to have flared-up 

 

10 It is not known if the fire crossed through direct flame contact, radiant heating and/or embers.
18

at least twice after the initial ignition. Additionally, there were flare-ups on the eastern 

side of Timber Creek Canyon on the morning of February, 28, 2011. 

Grass areas are reported by first responders to have had flame heights of about 0.1 m

(0.3 ft) Areas with shrubs such as mesquite and juniper experienced some torching with 

maximum flame heights of 3 m (10 ft) to 5 m (16 ft) observed in images. Higher flame 

heights might have occurred. 

Table 6 Damage and destruction to detached combustibles in Timber Creek Canyon.

Combustible Feature Number Damaged Number Destroyed

Deck 0 1

Playground Equipment 1 0

Secondary Structures 4 3

Vehicles 4 5

RV/Camper 0 1

Trailers 2 3

Planters 5 0

Lawn Mowers 2 0

Lawn Furniture 1 0

Firewood Piles 0 2

Trash/Stock Feed Piles 0 5

Small Cluster of Railroad Ties 0 1

As shown in Figure 7, the one destroyed structure in Timber Creek Canyon was 

determined to be burning for 41 minutes between the first signs of flames on the eastern 

roof and the last image of the structure when it was almost completely destroyed. The 

total burn time, while unknown, would have been greater than 41 minutes from ignition 

to the last flames on the structure. Field observations have shown that a destroyed 

structure, even if the structure has burned to the ground, can potentially continue to be a 

source of embers and continue posing a fire spread risk for hours after the structural 

collapse. One destroyed shed was also photographed by Karen Slagle and was shown to 

be burning for at least 15 minutes between the times of full involvement to complete 

destruction. Again, the total burn time, while unknown, would have been greater than 15 

minutes. The fire timeline contains information from different sources. The uncertainty 

associated with the timeline is specific to the individual events. A specific observation 

that was photographically documented may be very precisely located in time and space, 

while a set of confirmed observations that took place between two well defined/timeresolved activities may have larger associated temporal uncertainty. 

Table 7 Damage and destruction to linear features in Timber Creek Canyon.

Combustible Feature Meters Damaged Meters Destroyed

Landscaping Borders 45 (147 ft) 246 (807 ft)

Fences 929 (3049 ft) 149 (489 ft)

Retaining Walls 80 (261 ft) 29.5 (97 ft)
19

5.2 Defensive Action Categorizations

Figure 8 shows areas identified as being defended and the subsequent categorizations of 

primary structures as to a defensive action category. The one destroyed residential

structure at 338 Cactus Drive did not show any evidence of defensive actions once the 

primary structure was ignited. Defensive actions on this residential structure and 

combustibles around it contained the fire only after ignition and full involvement 

occurred. The one residential structure that had damage to an attached combustible at 

411 Roberts Drive had extensive defensive actions identified, including a defensive 

action on the attached damaged deck. 

Three structures as indicated in Figure 8 were categorized as defended because of 

observations made by field crews during field data collection or discussions field crews 

had with homeowners indicating the respective homeowner stayed and defended. All 

known flare-ups have been documented as being suppressed by first responders. Figure 

8 also shows areas where no defensive actions were identified. All of these had burn 

patterns that suggest the possibility of suppression, although these patterns could be due 

to pre-fire treatment, micro-scale topographic features such as a ditch (see Section 5.3),

and/or other factors. 

Table 8 shows a count of damaged and destroyed linear features such as fences or 

railroad ties used for landscaping, and damaged and destroyed detached combustible 

features, along with the number of features with identified defensive actions. Figure 8

and Table 8 highlight the main shortcoming with the defensive action identification 

method utilized. This shortcoming, the lack of identification of a defensive action around 

a particular structure or feature, does not mean that a defensive action did not occur on 

that feature.

5.3 Topographic Information

Figure 9 displays radar derived slope for the Timber Creek Canyon Community. Figure 

10 portrays radar derived aspect information. The flanking fire in the canyon going 

southeast to northwest was concentrated on south to north facing slopes. Additionally, 

the destroyed structure did lie in a small depression in this canyon, which might have 

influenced fire behavior. 

The destroyed structure was closest to this canyon feature when compared to all the

structures in Timber Creek Canyon. This destroyed structure was also on a Northwest 

aspect, providing direct exposure from the flanking fire. Slopes were relatively minor in 

the Timber Creek Canyon Community. Furthermore, small scale features such as 

drainage ditches did appear to influence fire behavior where it could be seen in images 

taken by Karen Slagle that the fire traveled faster up these ditches compared to 

Table 8 Damage and destruction to features in Timber Creek Canyon by defensive action.

Feature Number 

Damaged/Destroyed

Number Defended

Linear Features 23 8

Detached Combustible Features 32 4
20

neighboring areas. The radar data did not appear to capture these fine scale features, 

which appeared to have consequences for fire behavior. 

5.4 Structural Element Ignition Mechanisms

This section provides detailed accounts of damage and destruction on built properties in 

Timber Creek Canyon, as known. This type of information provides indications of 

ignition mechanisms. Additionally, this information will aid in the initial data 

segmentation into high and low exposure areas at a coarse scale. 

The damage to structural elements found on 411 Roberts Drive, near the origin, indicate 

the structure would have been destroyed without these defensive actions. These actions, 

consequently, provide significant clues to the ignition mechanism at this location. 

Figure 11 shows destroyed combustibles around 411 Roberts Drive.
21

Figure 5 Damage to structural elements in Timber Creek Canyon.

Background: City of Amarillo, used by permission, 

overlays NIST
22

Figure 6 Fire direction, fire road crossings, and general fire progression in Timber Creek Canyon. Prevailing wind 

direction at time of fire was from the Southwest.

Background: City of Amarillo, used by permission, 

overlays NIST
23

Figure 7 Specific time observations and general fire behavior in Timber Creek Canyon.

Background: City of Amarillo, used by permission, 

overlays NIST
24

Figure 8 Defensive action areas and primary structure categorizations in Timber Creek Canyon. Larger structures shown in imagery and not 

categorized to a defensive action status are secondary buildings and not residential.

Background: City of Amarillo, used by permission, 

overlays NIST
25

Figure 9 Radar derived percent slope in Timber Creek Canyon.

Background: City of Amarillo, used by permission, 

overlays NIST
26

Figure 10 Radar derived aspect in Timber Creek Canyon.

Background: City of Amarillo, used by permission, 

overlays NIST
27

It is believed the barn ignited first from fire in the directly adjacent wildlands. Embers 

from the burning barn then ignited vegetation, a deck and retaining walls near the 

residential structure at 411 Roberts Drive, in some unknown order. The combustible 

features were approximately 18 m (59 ft) from the barn. It is believed that burning from 

these features caused embers that accumulated in an exterior house corner and caused 

burning of a wall and elevated deck. There was also extensive destruction to burning 

railroad ties along the driveway, which were defended. Finally, the home had a wood 

roof. From discussions with first responders, there was no indication of roof ignition or 

defensive action on the roof. Additionally, there was no indication of any roof ignition in 

the field collected images.

The destruction to larger structural elements found on other properties with no destroyed 

residential structures is portrayed in finer detail in Figure 12. The shed destroyed at 334 

Cactus Drive was known to be contained by first responders. This destroyed shed is 

believed to have caused damage to a larger shed 3 m (10 ft) away. The damage to the 

shed led to the assumption it was defended. This damaged shed was a significant fuel 

source, 7 m (23 ft) from the primary structure.

The barn at 233 Quail Ridge Road was a large fuel source located over 40 m (131 ft) 

from the primary structure. It was known to be contained at some level. The two 

destroyed fence portions at 337 and 347 Cactus Drive were also known to be defended. 

The fence at 337 Cactus Drive was attached to the residential structure, and the fence at 

347 Cactus Drive was attached to a large secondary structure.

There is anecdotal evidence that defensive actions occurred at 500 Mesquite Drive. 

Additionally, the firewood pile was only partially consumed implying that it was most 

likely defended. The destroyed recreational vehicle/camper was 19 m (62 ft) from the 

main structure. The damaged railroad tie retaining wall at 346 Cactus Drive was not 

recorded as defended. The image shows some mechanical alteration of the feature. This 

alteration might have occurred after the fire. Although it cannot be determined if the 

feature was extinguished on its own or through human intervention, there is evidence that 

railroad ties can smolder or burn for extended periods. As stated earlier, the focus of the 

post-fire reconstruction was limited nominally to the first 12 hours after ignition. Mop-up 

or flare-ups that may have occurred after the initial fire front are not captured in this data 

collection.

The main fire front was photographed approximately 50 m (164 ft) from the one 

destroyed home at 338 Cactus Drive at 15:10. At 15:20 pm, the fire front had moved 

approximately 20 m (66 ft) past the most western non-destroyed secondary structure on

the property of 338 Cactus Drive. The first visible sign of smoke coming from the roof

of 338 Cactus Drive occured at 15:28 pm.

There were numerous combustibles found around the one destroyed home at 338 Cactus 

Drive. Figure 13 shows those structural elements that were known or suspected to have 

ignited prior to the ignition of the residential structure. There is a pile of unknown 

material greater than 30 m (98 ft) from the destroyed residential structure that ignited 

before flames or smoke are evident from the residential structure, but this was on the 

opposite side of the structure where flames first appeared. A vehicle 25 m (82 ft) from 
28

the residential structure is also shown to have ignited before the residential structure,

again on the opposite side of the initial ignition seen in the images. 

First responders observed a vehicle and fence on fire at the same time smoke was 

observed coming from the roof assembly of the residential structure. There were three 

destroyed vehicles in front of and to the southern side of the destroyed residential 

structure. First responder statements and images of flames coming from the roof indicate 

the ignition might have been through the eaves or an attic vent or space. The vehicle 

and/or fence were possible ignition sources as are other unidentified combustibles and/or 

vegetation. 

Other combustibles destroyed on 338 Cactus Drive are believed to be the result of the 

structure ignition and backing fires as the flanking fire spread north. First responder 

discussions indicate the fire on the property was contained after the residential structure 

ignition. Damaged and undamaged combustibles were concentrated on the interior part 

of the property, away from the initial flanking and backing fires that occurred after the 

main flanking fire moved through. Combustibles in the wildlands adjacent to the 

property on the south might have been significant sources of flames, radiant heat and 

embers.

5.5 Vegetative Element Ignition Mechanisms

The elements that are believed to have ignited and produced the initial flames of the 

Tanglewood Fire are shrub and grass wildlands in and around the origin, shown in Figure 

5. The ignition of these vegetative elements led to the ignition of some part of the 

combustibles discussed previously, as well as treated vegetation, such as Buffalo grass

(Buchloe Dactyloides (Nutt.) Engelm), found around residential structures. Untreated 

areas appeared to burn completely, and experienced the highest flame heights, aside from 

large man-made combustibles. 

Figure 14 portrays how vegetation treatment might affected burning. In some cases, such 

as the grazing, and possibly irrigation (shown in Figure 14), there is a clear line of 

demarcation between burning that occurred in areas that were known to be grazed and 

areas not grazed. Areas that appeared to be irrigated based on green vegetation were also 

able to stop the fire spread, as shown in Figure 14. The fire, however, burned right 

through some residential grasses, while others did not ignite from adjacent burning. 

Vegetation treatment, though not studied in this report, might have had consequences for 

vegetation burning. However, what is not clear is the exact contribution of vegetation 

treatment and defensive actions in reducing or preventing the burning of certain 

residential grass and grazing areas. Many treated vegetated areas appeared to be 

undergoing senescence due to the time of the year. It was consequently difficult to 

evaluate treatment levels. 

Additionally, it is quite possible that the fire might have stopped as a result of 

unidentified defensive actions. It seems likely that fire perimeter locations representing 

flanking and backing fire behavior (i.e. undefended areas along the fire perimeter to the 

north, south and west) areas shown as undefended in Figure 8, were defended to some 

extent. This scenario is likely due to the large number of first responders present in the 

area. Also, micro-scale topographic changes, coupled with the wind direction during the 

fire, might have affected fire behavior and vegetation burn patterns.
29

Figure 11 Ignition mechanisms in and around 411 Roberts Drive, close to the fire origin. Structure was defended.

Background: City of Amarillo, used by permission, 

overlays NIST

NIST Photo
30

Figure 12 Ignition mechanisms around non-damaged or non-destroyed residential structures in Timber Creek Canyon, NIST photos.

Background: City of Amarillo, used by permission, 

overlays NIST
31

Figure 13 Structural element ignition mechanisms at 338 Cactus Drive. Structural elements portrayed are known or suspected to be 

ignited prior to residential structure ignition. Fire direction was from southeast to northwest and the attached fence was on the north of 

the destroyed home, NIST photos.

Background: City of Amarillo, used by permission, 

overlays NIST
32

Figure 14 Pre-fire and post-fire imagery showing how vegetation treatments or landuse might have effected fire behavior. 

Approximate fire line is shown in red on image to the right.

Background: City of Amarillo, used by permission, 

overlays NIST
33

6.0 Plateau

The Plateau area is comprised of residential structures in different communities, 

including one structure in Timber Creek Canyon. These structures are termed the Plateau 

Community in this report and are grouped to help portray fire behavior over the study 

area. This section begins with a tabulation of the damage and destruction to structural 

elements in the Plateau Community. Generalized fire direction is presented and flame 

height estimates are portrayed. Fire timeline, flame heights and fire direction information 

are derived from radio logs, eyewitness discussions and field assessments. 

Areas where defensive actions were conducted in the community are detailed. 

Topographic characteristics are mapped and discussed. Primary structure categorizations 

to defensive action type are also portrayed. Finally, a qualitative examination of ignition 

mechanisms in this community is presented. 

6.1 Damage Assessment, Fire Direction and Fire Timeline

Figure 15 shows damage to structural elements from the Tanglewood Fire within the 

Plateau Community. As can be seen in Figure 15, residential structures were sparsely 

distributed. The residential structures to the south were outside the final fire perimeter. 

Residential structures inside the fire perimeter in this area saw no damage from the fire 

but there was damage to other combustible elements. 

A breakdown of damage to detached combustible features is shown in Table 9. Table 10 

shows damage to linear features. The extent of exposed but unburned combustible 

features is not listed as field data collection indicated that determining exposure in this 

complex topographic environment with varying winds has very large associated 

uncertainties. The destroyed secondary structures were small sheds, each over 20 m 

(66 ft) from the residential structure. The damaged fence was a metal fence with 

scorched wooden posts near 207 Quail Ridge Road.

Figure 16 shows fire direction and fire progression across the Plateau Community. There 

were some narrow dirt roads that the fire crossed but these areas were not assessed in the 

field, so exact fire cross locations are not known. There was, however, one statement by 

a first responder of the fire crossing Quail Ridge Road to the east of 215 Quail Ridge 

Road. There were no images obtained in this study of burning in the Plateau Community 

so timelines are more generalized. Figure 16 shows the main fire front burn times.

First responder discussions described the fire around 207 and 209 Quail Ridge Road as a 

flanking fire that was trying to push north. Erratic fire behavior was described in the 

Plateau Community, south of the Palisades Community. There was burning up to the 

ridge, torching of shrubs and winds described as greater than 32 kph (20 mph). 

Topographic features such as cliffs and rock outcrops might have influenced when and 

how the fire traveled into the canyon areas. 

The fire line was described by first responders as creeping south to the east of 215 Quail 

Ridge Road. Flame lengths around 215 Quail Ridge Road were described by first 

responders as being 0.3 m to 0.6 m high (1 ft to 2 ft) in 2.5 centimeter (1 in) tall grass. 

Burning yucca plants were described as producing embers in this area. 
34

6.2 Defensive Action Categorizations

Figure 17 shows areas identified as being defended and the subsequent categorizations of 

primary structures as to a defensive action category. All structures were identified as 

being defended except one. First responders anecdotally described 209 Quail Ridge 

Road as being defended by homeowners. Also, field crews observed a garden hose that 

might have been used to defend the property. The entire southern flank of the fire in the 

Plateau Community was identified as being defended. 

Damage or destruction to other structural elements found in the area was not specifically 

identified as being defended. The two destroyed secondary structures appeared to have 

been burned to the ground with no containment. The two damaged playground features 

were in low fuel areas. One was a trampoline with no signs of defensive actions. The 

second was a play structure with scorching and some burned features that might indicate 

defensive actions. The fence was a metal fence with wood posts that received scorching 

and possibly other destruction. 

6.3 Topographic Information

Figure 18 shows radar derived percent slope across the Plateau Community. Figure 19

shows radar derived aspect across the Plateau Community. The Plateau is relatively flat 

as can be seen in Figure 18. As shown in Figure 19, there are two plateau areas that are 

oriented towards the canyon area from southwest to northeast. The fire entered the 

canyon communities around these areas. 

6.4 Vegetation Element Ignition Mechanisms

The majority of structural element ignition mechanisms for the Plateau Community are 

described above and no further information is known in this regard. Again, though not 

studied specifically in this paper, vegetation treatment did appear to have consequences 

on fire behavior. For example, Figure 20 shows green grass around 209 Quail Ridge 

Road and the lack of fire in this area. While none were documented, the exact 

contributions of defensive actions, if any, are not known. 

However, field assessments at 209 Quail Ridge Road identified small areas of vegetation 

burning adjacent to noncombustible sections of the house as shown in Figure 21. It is not 

known if these areas were extinguished through manual intervention or if they 

extinguished independently. These burned areas were in the direction of the fire front 

and might have ignited due to ember accumulation against the wall possibly combined 

with the non-mowed grass directly adjacent to the house.

Table 9 Damage and destruction to detached combustibles in Plateau Community.

Combustible Feature Number Damaged Number Destroyed

Playground Equipment 2 0

Secondary Structures 0 2

Table 10 Damage and destruction to linear features in Plateau Community.

Combustible Feature Meters Damaged Meters Destroyed

Fences 195 (639 ft) 0
35

Figure 15 Damage to structural elements in the Plateau Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
36

Figure 16 Fire direction and fire timeline in Plateau Community. All times are on 2/27/2011.

Background: City of 

Amarillo, used by 

permission, overlays NIST
37

Figure 17 Plateau area defensive action locations and primary structure categorizations in the Plateau Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
38

Figure 18 Radar derived percent slope in Plateau area.

Background: City of 

Amarillo, used by 

permission, overlays NIST
39

Figure 19 Radar derived aspect in Plateau Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
40

Figure 20 Treated vegetation around 209 Quail Ridge Road that might have helped to stop fire from contacting house. Exact 

contributions of defensive actions are unknown.

Background: City of 

Amarillo, used by 

permission, overlays NIST
41

Figure 21 Two distinct vegetation ignitions adjacent to structure at 209 Quail Ridge Road. Red feature is 15 cm (6 in) long 

ballpoint pen, NIST photos.
42

7.0 Palisades South

This section begins with a tabulation of the damage and destruction to structural elements 

in the Palisades Community south of Lake Tanglewood. Also included in this section is a 

small area of the Lake Tanglewood Community south of the lake. Additionally, fire 

direction generalized from field observations of directional scorching are presented. Fire 

timeline information portrayed is derived primarily from radio logs. The fire behavior in 

this area is portrayed. Defensive actions conducted in the community along with 

defensive action categorizations of structures are also described. Topographic 

characteristics are mapped and discussed. Finally, identified structural and vegetative 

element ignition mechanisms are detailed.

7.1 Damage Assessment, Fire Direction and Fire Timeline

Figure 22 shows damage to structural elements from the Tanglewood Fire within the 

southern portion of the Palisades Community and a small selected portion of the Lake 

Tanglewood Community. As can be seen in Figure 22, there were three damaged 

residential structures, 17 destroyed residential structures and one residential structure 

with damage to an attached combustible deck. There was numerous damage and 

destruction to combustible and linear features. A breakdown of damage to detached 

combustible features is shown in Table 11. Damage and destruction to linear features by 

length is shown in Table 12. 

Figure 23 shows fire direction in the Southern Palisades and Lake Tanglewood portion of 

the study area. The fire directions shown in Figure 23 appeared to have been driven by 

weather, topographic features and available fuels. Fire traveled up and down canyons 

both in the direction of the wind as well as perpendicular to the main wind direction when 

topographic configurations aligned in this manner. Additionally, eyewitness observations 

Table 11 Damage and destruction to detached combustibles in Palisades South and selected portions 

of South Lake Tanglewood Community.

Combustible Feature Number Damaged Number Destroyed

Deck 0 2

Playground Equipment 13 0

Car Ports 0 2

Secondary Structures 7 35

Dock 0 1

Vehicles 5 15

RV/Camper 0 1

Boats 2 0

Trailers 6 6

Lawn Mowers 2 0

Firewood Piles 1 0

Corrals 2 0

Other Items (Building Material, Stock 

Feed, Small Railroad Ties and 

Retaining Walls, Trash/Brush Piles, 

Machinery, Grills, Propane Tanks, 

Stairs, Lawn Furniture, Tires, Wagons 

and Other Small Features)

20 58
43

described swirling fire behavior in Southern Palisades, which was verified in post-fire

field observations of directional scorching recorded near 450 Casino Drive. 

There were 9 locations where the fire was recorded as crossing roads. It is possible the 

fire crossed multiple locations along these roads. It is also possible that some of these 

fire crossings might have been a consequence of flames or radiant heat and not embers. 

For instance, there was a residential structure (mobile home) that was destroyed at 102 

Gary Drive. Flames or radiant heat from this large combustible feature might have 

ignited vegetation or the destroyed structure at 111 Gary Drive to the northeast. 

Additionally, there were two locations where the fire was recorded as jumping across 

Lake Tanglewood, a distance of approximately 23 m (75 ft). The most western location 

shown in Figure 23 was apparent in the field due to a large tree that experienced 

scorching on the southern side of the lake and burn patterns on the northern side of the 

lake in the direction of the fire. There was also one location where radiant heat was 

identified in the field as spreading the fire across a road, or possibly multiple roads, near 

Janet and Gary Drive.

Some specific time observations are shown in Figure 24. These observations all came 

from radio logs or the brief and not geographically complete flight by the Amarillo

sheriff helicopter. In addition to the specific time observations shown in Figure 24, there 

was an additional radio log report of numerous structures being on fire at 15:37 in 

Palisades. It is not clear if this refers to southern or northern Palisades or both. 

However, it can be seen in the helicopter fly over that 113 Janet Drive, while completely 

destroyed, still had smoke and flames present at 18:18. This indicates the possibility that 

the structure was ignited later, after the main fire front. The structure at 120 Russell 

Drive was completely destroyed with no flames or smoke emission visible at the same 

time. Additionally, some white smoke could be seen coming from the direction of 507 

Casino Drive, which was also identified by two first responders as burning later (i.e., 

around 17:00). 

First responders specifically described flames or destruction from 465 and 519 Casino 

Drive occurring early in the fire (e.g. around 15:00). The burning in the yards of 401 

Myrtle Drive and 401 Casino Drive were also described as occurring early in the fire (e.g. 

around 15:00). Flare-ups of combustibles and vegetation occurred into the morning of 

February 28th in the southern Palisades area. Significant flare-ups occurred later (e.g. 

after dark) and were all identified as being defended. These included a burning retaining 

wall that broke windows and possibly ignited soffits at 102 Gary Drive. The mobile 

home at 102 Gary Drive was also identified as being destroyed at this time (e.g. after dark 

around 23:45). Additionally, damaged combustibles along Hill Drive ignited later, while 

vegetation ignited earlier (around 14:45). Finally, some of the combustibles, including a 

large Box Car used for storage, on the south side of Jamie Lane across the street from 55 

Table 12 Damage and destruction to linear features in Palisades South and selected portions of 

Lake Tanglewood Community.

Linear Feature Meters Damaged Meters Destroyed

Landscaping Border 37 (121 ft) 263 (863 ft)

Fence 2026 (6647 ft) 375 (1230 ft)

Retaining Wall 1014 (3327 ft) 563 (1847 ft)
44

Jamie Lane were identified as burning late in the night of February 27th into the morning 

of February 28th. 

7.2 Fire Behavior

Figure 25 shows some general fire behavior observations inferred from post-fire ground 

and aerial imagery. As can be seen in Figure 25, there are three primary canyons that the 

fire traveled through. The fire did not, however, travel through all areas within each of 

these three canyons and appeared to be very topographically oriented in relation to the 

wind. Each of these canyons contained smaller sub-canyons and other topographic 

features. It is thought, though not confirmed, that the main fire front moved down each 

canyon at relatively the same time (i.e., somewhere between 14:30 to 15:00). A generally 

south facing oblique aerial image of the western most canyon in the southern Palisades 

Community is shown in

Figure 26. The fire might have entered this canyon from the plateau area in several 

different locations. These fire entrances, however, into this canyon appeared to be 

limited to topographic lows or drainage locations along the canyon rim where there were 

continuous fuels between the changes in geology types and less steep slopes. 

Conversely, cliffs, rocky outcrops and defensive actions (retardant drops) might have 

prevented the fire from entering the canyon in some locations. Fire behavior in this 

western canyon was more intense on the southeastern side of the canyon as can be seen in

Figure 26, where scorching of shrubs was prominent on the southeastern side and less so 

on the northeastern side. The divide of this change in fire intensity was along the dry 

drainage channel of the canyon. However, burning did occur in ground and structural 

fuels on the northeastern side of the canyon and into the properties on this side of the 

canyon. The middle canyon is portrayed in south and east facing oblique images shown 

in Figure 27 and Figure 28. Entry into this canyon was confined to an area on the 

western side of the canyon located to the northeast of 209 Quail Ridge Road. This area

was characterized by a narrow area of rock outcrops with vegetation allowing fire to 

travel into the canyon. Additionally, there were fewer cliffs in this area of the canyon. 

As shown in Figure 28, when the fire reached the bottom of the canyon, crowning fire 

occurred.

Stand replacing fires occurred on the southern side of Casino Drive in the middle canyon 

but only in certain sections on the northern side. Fire behavior in the wildlands to the 

west of 519, 513 and 507 Casino Drive was generally spotty and again topographically 

oriented. For example, 475 Casino Drive, the damaged home, was sheltered from fire 

behavior coming from the south to southwest due to topographic features.

As shown in Figure 27, fire then traveled up the canyon located to the south of Jamie 

Lane. Fire, however, did not enter the southern portion of the canyon. At least one fire 

retardant drop was delivered in that location and the contribution was unknown. Fire 

behavior consistently appeared to be more intense on what might be called the leeward 

side of topographic features compared to the windward side. In this area of the 

Tanglewood Fire, portrayed in Figure 278, the leeward side of the slopes was generally 

facing northeast. This is shown in Figure 27, where stand replacing fires occurred on the 

leeward side, while shrubs on the windward side were not consumed. This in part could 

be due to higher fuel loads or possibly an eddy effect of the wind/fire on these windward 

sides of topographic features. The video from the sheriff helicopter flight shows how fire 
45

behavior changed with topographic positions in the northern Lake Tanglewood 

Community as described in section 9. A similar effect could have occurred in this

Southern Palisades area. Figure 29 shows fire behavior in the eastern most canyon area 

of the Southern Palisades and Lake Tanglewood Communities. The same behavior is 

noticed in this canyon and adjacent areas where stand replacing or high intensity fires 

occurred on the leeward side of topographic features. Additionally, fire behavior was 

focused on the canyon bottom and somewhat into the southeastern side of the canyon 

with little or no fire behavior seen on the northwestern side of the canyon (north to 

northeast facing slopes).

7.3 Defensive Action Categorizations

Figure 30 shows locations of identified defensive actions along with the resulting 

categorization of structures as to a defended category. As shown in Figure 30, a power

line was down during the incident preventing first responders from entering into the 

eastern side of the Southern Palisades Community until after the main fire front had 

passed. The homeowner at 537 Casino Drive, however, was described as being present 

for the entire incident. 

Almost all homes on the western side of the downed power line were shown to have been 

protected. Homes at 365 and 375 Casino Drive and 450 Myrtle Drives did not have 

defensive actions identified. Defensive actions, however, along Casino Drive likely 

prevented fire from entering these properties as no burned features were identified. The 

sprinklers left on at 401 Casino Drive appeared to coincide with the final fire perimeter

on this property. It is not, however, known if it was the sprinkler being on during the 

time of fire, continued historic use of the sprinkler to treat the lawn in the specified area,

or a combination of both that ultimately stopped the fire.

The defensive action that occurred at 102 Gary Drive occurred later in the incident, after 

the adjacent structure was destroyed. The burning residential structure at 507 Casino

Drive was contained (i.e. fire was prevented from spreading beyond that structure) and it 

is believed this is one of the last homes to burn in this southern Palisades area. This 

containment along with containment of a destroyed large secondary building at 100 Janet 

Drive resulted in 100 Janet Drive being categorized as protected. 

The residential structure at 475 Casino Drive had no specific defensive actions identified 

but there was evidence of mechanical alteration of burned straw bales adjacent to the 

home. Consequently, the structure was classified as protected. The residential structure 

at 450 Casino Drive had a carport destroyed next to the home but no specific defensive 

actions were identified. Interior homes along Janet Drive did not have defensive actions 

identified but there was also limited fire behavior in this area. 

Table 113 shows a count of damaged and destroyed linear features, and damaged and 

destroyed detached combustible features, along with the number of features with 

identified defensive actions. Again, Table 13 highlights the main shortcoming with the 

defensive action identification method utilized. This shortcoming, the lack of 

identification of a defensive action around a particular structure or feature, does not mean 

that a defensive action did not occur.
46

7.4 Topographic Information

Figure 31 portrays percent slope for Palisades South and selected portions of Lake 

Tanglewood Communities. As mentioned above, topography appeared to play an 

important role in fire behavior in the Palisades South and selected portions of Lake 

Tanglewood Communities. The steepest slopes were found along the rim of the canyon 

and these steep slopes or cliffs appeared to prevent fire spread from the plateau into the 

communities. The fire appeared to enter the canyons in areas of more moderate slopes 

along the canyon rim. Microscale steep slopes found along the canyon bottoms might 

also have played a role in fire behavior in this portion of the study area. 

As can be seen in Figure 32, damage and destruction was more prevalent on one side of a 

particular canyon compared to the other side. The side facing the wind appeared to have 

more damage. There is damage and destruction into the interior of the Southern 

Palisades Community. As discussed below, some of this might have been due to 

structure to structure fire spread.

7.5 Structural Element Ignition Mechanisms

Structures located along Hill Drive and portions of Casino Drive (the western canyon 

described in section 7.2 above) exhibited some damage and destruction to structural 

elements. Many first responders were in this area and some of the damaged features were 

specifically identified as defended. As described above, in Section 7.2, structures on Hill 

Drive received less exposure to the fire compared to those on the opposite side of the 

Canyon on Casino Drive. Even within specific canyon sides, different exposures were 

experienced based on other topographic features present.

The primary damage close to homes found in this area was to a storage shed located on 

110 Hill Drive and railroad tie retaining walls and borders located on the parcels at 110 

and 120 Hill Drive and 401 and 430 Casino Drive. These damaged features were close to 

or directly adjacent to wildlands. The damaged storage shed was over 19 m (62 ft) from 

the closest primary structure. Damaged railroad tie retaining walls were 9 m (29 ft) away 

from the residential structure located at 110 Hill Drive and about 19 m (62 ft) away from 

the residential structure located at 120 Hill Drive. 

The primary structure at 400 Casino Drive was also damaged. This was due to a pile of 

trash bags with unknown debris that burned and melted a vinyl soffit. The radiant heat or 

flames appeared to be sufficient to melt the vinyl soffit but no scorching to the underlying 

enclosed wood soffit was document by field observers. The brick siding was scorched. 

Table 13 Damage and destruction to features in Southern Palisades and selected portions of North

Lake Tanglewood categorized by identified defensive actions.

Feature Number 

Damaged/Destroyed

Number Identified as 

Defended

Linear Feature 32 3

Detached Combustible 

Features

138 4
47

Figure 22 Damage to structural elements in the southern Palisades Community and selected portions of the South Lake 

Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
48

Figure 23 Fire direction in Southern Palisades and South Lake Tanglewood Community. The main fire front moved 

through area between 14:30 and 15:30 on 2/27/2011.

Background: City of 

Amarillo, used by 

permission, overlays NIST
49

Figure 24 Palisades South and portions of South Lake Tanglewood with specific time observations on 2/27/2011. 

Background: City of 

Amarillo, used by 

permission, overlays NIST
50

Figure 25 General fire behavior observations and location of retardant drop in southern Palisades community and portions of South Lake Tanglewood.

Background: City of 

Amarillo, used by 

permission, overlays NIST
51

Figure 26 Post-fire south facing oblique imagery showing results of higher intensity fire on the southeastern side (northeast facing) of the canyon 

compared to the northwestern side.

Background: City of 

Amarillo, used by 

permission, overlays NIST
52

Figure 27 Post-fire south facing oblique imagery showing results of fire behavior in the upper portion of the middle canyon area of 

Southern Palisades Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
53

Figure 28 Post-fire east facing oblique imagery showing results of fire behavior in the bottom of the middle canyon area of 

Southern Palisades Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
54

Figure 29 Post-fire south facing oblique imagery showing results of fire behavior in the eastern most canyon area of the Southern Palisades and South Lake 

Tanglewood Communities.

Background: City of 

Amarillo, used by 

permission, overlays NIST
55

Figure 30 Defensive action locations and primary structure categorizations in Southern Palisades and selected areas of 

South Lake Tanglewood Communities.

Background: City of 

Amarillo, used by 

permission, overlays NIST
56

Figure 31 Radar derived percent slope in Palisades South and selected portions of South Lake Tanglewood Communities.

Background: City of 

Amarillo, used by 

permission, overlays NIST
57

Figure 32 Radar derived aspect in Palisades South and selected portions of South Lake Tanglewood Communities.

Background: City of 

Amarillo, used by 

permission, overlays NIST
58

This feature was not specifically recorded as defended and the burned feature appeared to 

be completely consumed. 

Other damage found around 400 Casino Drive was to railroad tie borders, stairs, and

retaining walls. Additionally, a bird feeder, plastic trash cans and a partially melted grill 

cover were damaged or destroyed from ember exposure. All but the grill cover and the 

trash pile described above were directly adjacent to wildlands. 

The structure on 400 Casino Drive was on a terraced platform that might have helped 

direct fire and embers away from this house. The lack of damage and scorching to other 

features located around the house provide evidence for a lack of exposure. The destroyed 

trash piles were located closest to the adjacent wildlands. Additionally, the damage to the

grill cover was minor, with ember damage absent on other parts of the cover or other 

features (e.g. clothed lawn furniture) located adjacent to the grill.

Furthermore, damage to lawns and structural elements on the opposite side of Casino 

Drive from 400 Casino Drive occurred in topographic locations across from the canyon 

or areas with topographic configuration that might have helped influence fire behavior. 

However, the exact contribution of defensive actions and exposure conditions are not 

known. For example, the terracing might have provided first responders a means to 

defend the property. 

Damage or destruction to structural elements along Casino Drive in the middle canyon 

area described above was universal among all primary structures found adjacent to this 

canyon. There were, however, three homes that received varying degrees of damage and 

were not destroyed. These were 450 and 475 Casino Drive and 102 Gary Drive.

450 Casino Drive is the most western home adjacent to the middle canyon. An attached

car port to the structure was destroyed. The attachment appeared to be metal to brick 

siding. There were numerous first responders in the area but it is not known if this 

particular home was defended or if the brick siding and other structural features 

prevented the residential structure 

from igniting. The volume of fuels 

this car port contained is not 

known. Fire burned directly up to 

this house in low grasses and no 

damage or scorching was observed

on the brick siding.

475 Casino Drive also had damage 

to various structural elements 

attached and adjacent to the house 

as well as destruction of a large 

secondary building. Wildland 

vegetation burning was spotty 

around 475 Casino Drive with 

localized intense burning. 

Numerous features were damaged 

including hay bales leading from 

Figure 33 Burned hay bales leading from destroyed 

secondary structure to primary structure causing 

scorching on the brick siding. Categorization of 

defensive actions is unknown, NIST photo.
59

the destroyed structure to the residential structure as shown in Figure 33. The defensive 

action categorization is not known. However, there were other partially burned items and 

cut burned trees (time of cutting not known), which could indicate defensive actions.

102 Gary Drive is the other non-destroyed home in this middle canyon area. This home 

was damaged but the damage

appeared to be from reignitions of vegetation and 

rail road ties adjacent to the 

home. These items were 

identified as being defended 

after 17:00 on February 27th. 

There was also destruction of 

some unidentified attached 

feature as shown in Figure 34, 

which appeared to be caused 

by burning of the adjacent 

mobile home. This 

unidentified feature was not 

identified as being defended 

and the brick likely protected 

the home from the burning of 

these unidentified objects. 

The burning of these objects, 

however, did not appear to 

produce flames of significant 

height as is evident in Figure 34, which resulted in damage to the wood eaves found in 

one location above the unidentified features.

While the brick and metal siding likely helped to protect the non-destroyed residential 

structure at 102 Gary Drive, there was also evidence the structure was protected by a 

specific topographic configuration. There was a canyon to the west of 102 Gary Drive 

that saw a stand replacing fire as shown in Figure 35A. This canyon might have helped 

direct fire away from the home as is evident in Figure 35B, where a juniper bush, yucca 

plants, and rail road ties had minimal scorching and no burning, while vegetation and 

features to both the north and south of this area saw extreme fire behavior.

It should also be noted that structure to structure fire spread might have occurred in the 

Southern Palisades Community. The secondary structure at 475 Casino Drive appeared 

to have helped spread the fire directly to the residential structure at this address. 

Secondary structures at 75 Jamie Lane and 465 Casino Drive might also have ignited the 

residential structures on these properties. As mentioned above, structure to structure fire 

spread might have occurred from the mobile home at 102 Gary Drive to the residential 

structure at 111 Gary Drive. The burning of Gary Drive might also have resulted in the 

ignition of 113 Janet Drive. Other structure to structure fire spread might also have 

occurred.

Figure 34 Unidentified burned features adjacent to the 

northern side of the residential structure at 102 Gary Drive.

These features are believed to be ignited by the burning 

mobile home to the north of the brick residential structure, 

NIST photo.
60

7.6 Vegetative Element Ignition Mechanisms

As shown in Figure 36, fire also spread into the yards of some properties along Hill Drive 

as well as on Casino 

Drive, burning into the 

residential grass areas. 

It is assumed that the 

fire was suppressed in 

these yards. However, 

as shown in Figure 36, 

the fire did not travel 

into the grass on some 

properties. These 

properties can be 

shown to exhibit a 

higher degree of 

redness as shown in the

pre-fire false color 

display shown in 

Figure 36. Red areas 

in color-infrared 

imagery displayed as a 

false-color composite 

portray areas that have 

photosynthetically 

active vegetation. This 

imagery, however, was 

flown two years prior 

to the incident and 

might not reflect 

pertinent ground 

conditions. 

Nonetheless, the grass 

areas that are redder 

might have had more 

treatment (i.e., water 

and possibly nutrition) 

that could have helped 

prevent fire spread on 

these properties. It is 

also possible that first 

responders suppressed 

the fire and treatments, either those present or lack thereof, on the yards did not affect fire 

behavior. Also, the properties on Hill Drive appeared to be located on a less exposed 

area due to topography and wind. Other areas along Janet Drive and Gary Drive also 

showed burn patterns that corresponded to possible vegetation treatment in pre-fire 

imagery. 

Figure 35 A: Stand replacing fire in the canyon to the west of 102 

Gary Drive. B: Vegetation and building features with minimal 

damage at the top of the canyon, indicating topographically 

influenced fire behavior. Image taken from the south side of 102 

Gary Drive looking north, NIST photos.

A

B
61

8.0 Palisades North and Tangle Aire

This section begins with a tabulation of the damage and destruction to structural elements 

in the Palisades Community North of Lake Tanglewood. Also included in this section is 

a small area of the Lake Tanglewood Community North of the lake and the Tangle Aire 

Community. Additionally, fire direction generalized from field observations of 

directional scorching are presented. Fire timeline information is derived from radio logs 

and some images.

This section also discusses fire behavior in the Palisades North, sections of South Lake 

Tanglewood and Tangle Aire Communities. Defensive actions conducted in the 

community along with defensive action categorizations of structures are also described. 

Topographic characteristics are mapped and discussed. Finally, identified structural and 

vegetative element ignition mechanisms are detailed.

8.1 Damage Assessment, Fire Direction and Fire Timeline 

Figure 37 shows damage to structural elements from the Tanglewood Fire within the 

Palisades North, Tangle Aire and portions of North Lake Tanglewood Communities. 

There were two damaged residential structures, 15 destroyed residential structures, two 

residential structures with damage to attached combustibles and 27 residential structures 

with no damage. There was numerous damage and destruction to detached combustible 

Figure 36 Portions of the fire perimeter overlaid on pre-fire (2009) color-infrared imagery. 

Fire did not travel into redder residential grass areas. This could be due to exposure 

conditions, defensive actions, pre-fire vegetation treatment or a combination of these factors.

Background: City 

of Amarillo, used 

by permission, 

overlays NIST
62

and linear features. A breakdown of damage to detached combustible features is shown 

in Table 14. Damage and destruction to linear features by length is shown in Table 15.

Table 14 Damage and destruction to detached combustibles in Palisades North, Tangle Aire and 

selected portions of North Lake Tanglewood Communities.

Combustible Feature Number 

Damaged

Number 

Destroyed

Short Linear Features (Fence, Retaining Walls, 

Railroad Ties) 7 4

Playground Equipment 3 1

Car Ports 0 1

Secondary Structures 2 18

Machinery 1 4

Vehicles 3 2

RV/Camper 0 1

Boats 1 2

Trailers 2 2

Lawn Mowers 0 4

Firewood Piles 2 0

Building Material Piles 3 5

Trash Piles 0 3

Grills 1 3

Other Items (Propane Tanks, Stairs, Hot Tub, 

Lawn Furniture, Tires, Work Bench, Planters, Gas 

Can, Lawn Art, Wheelbarrow, Burn Barrel and 

Other Small Features)

8 12

Figure 38 shows fire direction in the North Palisades, Tangle Aire and South Lake 

Tanglewood portion of the study area. As with other areas, weather, topographic features 

and available fuels appeared to be the main drivers for fire behavior. It should also be 

noted that wind shifts that occurred late in the evening of February 27th caused flare-ups 

that burned in a southern direction. In fact, 114 Palisades Boulevard survived the main 

fire front moving through the area around 15:00, but was destroyed later from these flareups and change in fire direction. 

Table 15 Damage and destruction to linear features in Palisades North, Tangle Aire and selected 

portions of North Lake Tanglewood Communities.

Linear Feature Meters Damaged Meters Destroyed

Fence 66 (216 ft) 81 (266 ft)

Retaining Wall 102 (335 ft) 25 (82 ft)

There were three locations along Canyon Creek Drive where the fire jumped the road. It 

is, however, not known if the embers came from the southern side of the lake or from 

burning wildlands along the northern edge of the lake. The fire jump at 555 Canyon 

Creek Drive resulted in the fire traveling north through the wildlands along Palisades 

Boulevard and jumping over to the wildlands between Palisades Boulevard and Saint 

Andrews Road. The fire jumped Saint Andrews Road and ignited the most southern 

destroyed homes between Saint Andrews Road and Exmoor Road. The fire continued to 

travel north to northeast, jumping Bayshore Road in three locations and jumping Tangle 

Aire Point in one location as noted in Figure 38. 
63

Figure 39 shows specific burning time observations from radio logs and images taken of 

the area. The main fire front was estimated to have moved through the area shown in 

Figure 38 between 15:00 to 15:30. Initial structure ignitions occurred shortly after or 

during this time frame, four hours after the initial fire ignition. It is estimated that all 

residential structures in the area shown in Figure 39 were destroyed by 17:00 with the 

exception of 114 Palisades Boulevard, which survived the main fire front and was 

destroyed later on the evening of the 27thor the early morning hours of the 28th when the 

wind was coming from the north. 

8.2 Fire Behavior

Figure 40 portrays some general fire behavior observations inferred from post-fire ground 

and aerial imagery. As mentioned above, the fire jumped Lake Tanglewood in some 

specific locations. Ember spread did not appear to be ubiquitous in the southern portion 

of the Northern Palisades community as many man-made and natural combustibles did 

not burn in this area. 

The fire traveled up the west side of Palisades Boulevard. There was crowning fire 

behavior in the wildlands between Palisades Boulevard and Saint Andrews Road. This 

crowning fire behavior continued up the canyon to the Tangle Aire Community where 

torching of trees was observed by first responders and in images taken in the area. The 

canyon to the south of 155 Saint Andrews Road also experienced crowning fire behavior 

that was very topographically oriented and was a function of local winds.

The fire jumped from wildlands to the south of Tangle Aire Point into Buffalo grass

found on the property of 13800 Tangle Aire Point. Additionally, the fire jumped from 

either burning structures or wildlands on Exmoor Road into Buffalo grass found on 136 

Bayshore Drive. As mentioned above, there was a change in wind direction in the night 

of February 27

th which caused fire spread from the north (due a north wind) and resulted 

in areas that were not burned from the initial fire front movement, which burned later.

8.3 Defensive Action Categorizations

Figure 41 shows locations of identified defensive actions along with the categorization of 

structures as to a defended category. As shown in Figure 41, most homes that were 

destroyed had no specific defensive actions identified during passage of the first main fire 

front. There were containment actions on 143 Bayshore Drive as well as on some 

unidentified structures along Exmoor Road, but these containment actions appeared to be 

after most of the residential structures were fully involved. The mobile home at 130 

Exmoor Road also had the front porch pulled off but the fire had spread underneath the 

home and the action was not successful. The residential structure at 114 Palisades 

Boulevard was protected during passage of the second main fire front when winds 

changed. The structure had already ignited, however, and was ultimately destroyed.

The residential structure at 144 Exmoor Road had a very small ember ignition on the 

deck extinguished by homeowners. The homeowner at 124 Saint Andrews Road watered 

down the residential structure during the time 131 Exmoor Road was burning. This action 

was taken, according to the homeowner, to prevent ember ignitions from the burning of 

this structure. The home on 140 Bayshore Drive had an attached wood fence 

extinguished by first responders. The homes on 13844 Tangle Aire Point and 120 Glen 
64

Eagle Trail had detached wood fences extinguished by homeowners. A detached wood 

fence on 125 Bayshore Drive was also extinguished by first responders. The home on 

585 Canyon Creek Drive appeared to have had burning mulch and attached stairs 

extinguished early by a first responder. Table 16 identifies damaged and destroyed linear 

and detached combustible features by identified defensive actions. 

The residential structure at 155 Saint Andrews Road might have been protected by 

homeowners at least indirectly, through extinguishing burning vegetation to the north of 

155 Saint Andrews. The one home on Exmoor Road identified as No Actions was a 

concrete abandoned building with fire not coming close to the building. Homes in the 

southwest corner of the community as shown in Figure 41 were outside any exposure 

from fire. Other mapped defensive actions areas around destroyed residential structures 

shown in Figure 41 display mop-up actions occurring after the homes were destroyed and 

burning was largely completed. 

8.4 Topographic Data

Figure 42 shows radar derived slope for the Northern Palisades, Tangle Aire and selected 

areas of North Lake Tanglewood Communities. Slopes were relatively moderate in many 

of the areas receiving the majority of the damage and destruction from the fire. In certain 

northern areas, cliffs appeared to stop fire spread into the plateau area of Tangle Aire. 

The fire appeared to travel up canyons into Tangle Aire in areas where slopes were more 

moderate.

Radar derived aspect is shown in Figure 43. As can be seen in Figure 43, there is also 

complex topography found in this portion of the study area. Many destroyed residential 

structures appeared to be on or close to south and southwest slopes. Structure to structure 

fire spread might have resulted in additional damage and destruction to areas outside 

these south and southwest facing slopes. 

8.5 Structural Element Ignition Mechanisms

Fences, rail road ties and secondary structures were ignition mechanisms in the Northern 

Palisades, Tangle Aire and selected portions of Lake Tanglewood communities. As 

shown in Table 16, there were several fences extinguished by first responders. 

Additionally, railroad ties were identified as being damaged or destroyed with some 

identified as being defended, though these could not be linked to a specific feature. Also, 

a deck was ignited at one location by minor ember accumulation at 144 Exmoor Road 

and extinguished by homeowners, as shown in Figure 44. Figure 44 demonstrates the 

need for discussions with first responders and homeowners to determine defensive 

actions as no signs of actions were present at this home. This also demonstrates that

when structural items are damaged, researchers should assume a defensive action as 

opposed to assuming no defensive action occurred, as stated in Quarles et al6and Foote et 

al.

14

 Fire underneath mobiles homes was also identified as an ignition mechanism.

Table 16 Damage and destruction to features in Northern Palisades, Tangle Aire and selected 

portions of North Lake Tanglewood categorized by identified defensive actions.

Feature Number 

Damaged/Destroyed

Number Identified 

as Defended

Linear Feature 65 13

Detached Combustible Features 95 8
65

Figure 37 Damage to structural elements in the northern Palisades, Tangle Aire and selected portions of North Lake Tanglewood Communities.

Background: City of 

Amarillo, used by 

permission, overlays NIST
66

Figure 38 Fire direction and fire timeline in north Palisades, Tangle Aire and selected portions North Lake Tanglewood Communities. The main fire 

front moved through this area between 15:00 and 15:30 on 2/27/2011. A wind shift occurred later on 2/27/2011 that caused flare-ups and fire direction 

from the north. The second fire front, portrayed as an orange arrow above, was observed as one fire direction indicator in the field observed through 

radiant heat damage and confirmed through eyewitness observations. 

Background: City of 

Amarillo, used by 

permission, overlays NIST
67

Figure 39 Palisades North, Tangle Aire and portions of North Lake Tanglewood specific time observations on 2/27/2011 from radio logs and images. 

114 Palisades Boulevard was destroyed late in the night of 2/27/2011 or in the early morning hours of 2/28/2011 after a wind shift from the north 

occurred. It is believed all other destroyed structures burned before 17:00 on 2/27/2011.

Background: City of 

Amarillo, used by 

permission, overlays NIST
68

Figure 40 Fire behavior observations in Palisades North, Tangle Aire and portions of Lake Tanglewood North communities.

Background: City of 

Amarillo, used by 

permission, overlays NIST
69

Figure 41 Defensive action locations and primary structure categorizations in Northern Palisades, Tangle Aire and selected areas of North Lake 

Tanglewood Communities.

Background: City of 

Amarillo, used by 

permission, overlays NIST
70

Figure 42 Radar derived percent slope in Northern Palisades, Tangle Aire and selected areas of North Lake Tanglewood Communities.

Background: City of 

Amarillo, used by 

permission, overlays NIST
71

Figure 43 Radar derived aspect in Northern Palisades, Tangle Aire and selected areas of North Lake Tanglewood Communities.

Background: City of 

Amarillo, used by 

permission, overlays NIST
72

Structure to structure fire spread might have 

been prevalent in this portion of the study area. 

The homeowner at 124 Saint Andrews Road 

saw flames from 135 Exmoor Road spread to 

134 and 130 Exmoor Road. Ember ignitions 

from these burning homes were extinguished by 

the homeowner at 124 Exmoor Road. It is 

possible that the numerous secondary structures 

to the east of 135 and 131 Exmoor Road ignited 

these residential structures. Additionally, there 

is one image of 128 Exmoor Road fully 

involved with 130 Exmoor Road beginning to 

be ignited as shown in Figure 45.

8.6 Vegetative Element Ignition Mechanisms

Vegetation treatment also appeared 

to have consequences for fire 

behavior. For example, Figure 46

shows field delineated burned 

vegetation around some homes in 

the Tangle Aire Point Community. 

Areas portrayed in bright red 

indicate healthy, photosynthetically 

active vegetation. As can be seen in 

Figure 46, the fire sometimes 

stopped where the treatment began, 

such as on the properties of 13901 

and 13841 Tangle Aire Point. It is, 

however, not known if it was a 

combination of defensive actions 

and vegetation treatment or treatment alone that resulted in the fire stopping in these 

locations. Other areas show similar patterns in this portion of the study area but again, it 

could not be determined if treatment alone stopped fire spread or a combination of 

treatment and defensive actions.

9.0 North Lake Tanglewood 

This section begins with a tabulation of the damage and destruction to structural elements 

in the North Lake Tanglewood Community. Additionally, fire direction generalized from 

field observations of directional scorching are presented. Fire timeline information is 

derived from radio logs, and some images and video.

This section also discusses fire behavior in the North Lake Tanglewood Community. 

Defensive actions conducted in the community along with defensive action

categorizations of structures are also described. Topographic characteristics are mapped

and discussed. Finally, identified structural and vegetative element ignition mechanisms

are detailed.

Figure 44 Ignited deck, which was 

extinguished by homeowners, NIST 

photo.

Figure 45 Fully involved residential structure at 128 

Exmoor Road igniting residential structure at 130 

Exmoor Road, Photo Gordon Ivy, used by permission.
73

9.1 Damage Assessment, Fire Direction and Fire Timeline 

Figure 47 shows damage to structural elements from the Tanglewood Fire within the 

North Lake Tanglewood Community. There were two damaged residential structures, 

one destroyed residential structure, and 37 residential structures with no damage. There 

was numerous damage and destruction to combustible and linear features. A breakdown 

of damage to detached combustible features is shown in Table 17. Damage and 

destruction to linear features by length is shown in Table 18.

Table 17 Damage and destruction to detached combustibles in North Lake Tanglewood Community.

Combustible Feature Number Damaged Number Destroyed

Railroad Tie Retaining Walls 1 1

Decks 1 2

Hot Tub 0 1

Secondary Structures 1 7

Stairs 1 0

Building Material 0 1

Firewood 1 1

Lawn Furniture 2 0

Trailers 1 0

Lawn Mowers 0 2

Door Mat 0 1

Wagon 1 0

Figure 48 shows fire direction in the North Lake Tanglewood Communities. As with 

other areas, weather, topographic features and available fuels appeared to be the main 

drivers for the fire behavior. There were three locations along the west side of Port-OCall Drive where the fire jumped the road. The fire also jumped the road from burning 

Figure 46 Field delineated burned vegetation around Tangle Aire Point overlayed on a false color 

composite pre-fire image. Red areas show healthy photosynthetically active vegetation.

Background: City of 

Amarillo, used by 

permission, overlays NIST
74

structural elements on the east side of Port-O-Call drive to unknown features at 102 PortO-Call Drive. The fire jumped from some location on the west side of Bayshore Drive 

around 115 Bayshore Drive to 101 Bayshore Drive. The fire also jumped from the 

destroyed structure at 102 Port-O-Call Drive to grass on 113 Bay Rock Circle. 

Table 18 Damage and destruction to detached linear features in North Lake Tanglewood 

Community.

Linear Feature Meters Damaged Meters Destroyed

Landscaping Border 110 (361 ft) 0

Fence 457 (1499 ft) 4 (13 ft)

Retaining Wall 219 ( 719 ft) 319 (1047 ft)

Figure 49 portrays some specific time observations of burning features in the North Lake 

Tanglewood Community. It is difficult to precisely portray fire progression through 

vegetation in this area as the fire appeared to move rapidly through some areas and 

slowly through others. Fire was observed moving through flammable vegetation in the 

areas behind 119, 117, 103 and 105 Port-O-Call Drive. The detached garage at 103 PortO-Call Drive was fully involved at 16:33. At 17:17 there were high (taller than the 

residential structure) flame heights around 100 Camino Alto. The fire was described as 

moving rapidly towards the golf course north of Lago Vista Street at 17:28. 

The one destroyed structure at 102 Port-O-Call Drive had the roof observed as fully 

involved at 16:55 with an image of full involvement also recorded at 17:48. At 18:11 the 

Amarillo Sheriff Helicopter flight showed the structure as a foundation. The final flames 

of the main fire front were observed through vegetation around the end of the mapped 

fire perimeter at approximately 18:18 by the Amarillo Sheriff Helicopter flight. Various 

flare-ups of vegetation and structural elements were observed in the North Lake 

Tanglewood Community into the morning of February 28th.

9.2 Fire Behavior

Fire behavior in the North Lake Tanglewood Community exhibited some similar 

topographically influenced fire behavior as described in the Southern Palisades 

Community. More intense fire behavior on the wind facing side of slopes was shown in 

the Amarillo Sheriff Helicopter flight in Figure 50, which also portrays the result of this 

fire behavior in the post-fire imagery. There is a complex interaction between fuels and 

topography, the exact components of which are identified but not studied in this paper. 

The burn patterns shown in Figure 50 and observed in other areas described in the 

Southern Palisades Community section above were also observed in other areas in the 

North Lake Tanglewood Community.

9.3 Defensive Action Categorizations

Figure 51 shows locations of identified defensive actions along with the resulting 

categorization of structures as a function of defensive actions. Defensive actions were 

extensive in the North Lake Tanglewood Community. They started with the arrival of the 

fire front and continued into the morning hours of February 28. Defensive actions were 

occurring at the time 102 Port-O-Call Drive was ignited and containment of this structure 

occurred. Numerous first responder teams stopped the high intensity fire shown in Figure 

50 from spreading east across Tanglewood Drive. First responders stopped fire spread 

both to the north of Haddock Drive and along the southern fire perimeter north of 
75

Bayshore Drive. Suppression of fire spread by first responders also occurred in the 

occluded flammable vegetation area in the back yards of 101, 103, 105, 117, 119 and 121 

Port-O-Call Drive. However, some fire spread might have been stopped by vegetation 

treatment described below. 

Many features, including fences and railroad ties were recorded as being defended 

multiple times by different first responders using water. First responders also stopped 

fire spread in the wildland behind 142 to 154 Port-O-Call Drive and the fire spread at 113 

Bay Rock Circle was also described as being extinguished by first responders. Only 

three homes in this area had no specific defensive actions identified namely 116, 115 and 

110 Bayshore Drive. There was a small secondary structure and lawn mower destroyed 

at 116 Bayshore Drive with no specific containment actions determined for these 

features. Fences, borders and railroad tie retaining walls were damaged at 110 Bayshore 

Drive, indicating the possibility of defensive actions for these features; though these 

features were not specifically identified as defended. The property at 115 Bayshore 

Drive did not have any damaged or destroyed features identified. Table 19 numerates 

damaged and destroyed linear and combustible features by identified defensive actions. 

9.4 Topographic Information

Figure 52 portrays radar derived percent slope for the North Lake Tanglewood 

Community. Figure 53 portrays radar derived aspect for the North Lake Tanglewood 

Community. As mentioned above, topography appeared to play an important role in fire 

behavior in the North Lake Tanglewood Community. The exact contribution of 

topography and fuels is not examined in this study. Nonetheless, the steepest slopes were 

found along the rim of the canyon and these steep slopes or cliffs appeared to prevent fire 

spread into the northern plateau area of the Lake Tanglewood Community. As with the 

fire entering the canyon area in the Southern Palisades Community, fire appeared to only 

enter the plateau area of the Lake Tanglewood Community in areas of moderate slopes.

In fact, cliffs to west of 100 Camino Alto appeared to cause the flames described by first 

responders as jumping over the top of the house resulting in radio logs incorrectly

reporting the house on fire. Moderate slopes along the cliff to the west of 100 Camino 

Alto provided locations where the fire was directed away from the house and towards 

wood fences and retaining walls as described below. The home appeared to see low

intensity fire behavior directly to the west and close to the home (< 8 m (26 ft)) where 

there was green vegetation as described below. Finally, topographic configurations along 

with fuels might have had consequence for structure ember spread from 102 Port-O-Call 

Drive to the Buffalo grass burned at 113 Bay Rock Circle. 

Table 19 Damage and destruction to features in North Lake Tanglewood Community categorized by 

identified defensive actions.

Feature Number Damaged/Destroyed Number Defended

Linear Feature 27 16

Detached Combustible 

Features

21 12
76

Figure 47 Damage to structural elements in the North Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
77

Figure 48 Fire direction and fire timeline in North Lake Tanglewood Community. The main fire front moved through the area between 15:00 and 

18:30 on 2/27/2011. 

Background: City of 

Amarillo, used by 

permission, overlays NIST
78

Figure 49 North Lake Tanglewood specific time observations on 2/27/2011 from radio logs and images.

Background: City of 

Amarillo, used by 

permission, overlays NIST
79

Figure 50 Fire behavior changes coincident with topography. Side directly exposed to wind (left) saw limited scorching and no torching of trees in 

post-fire imagery, and a low intensity ground fire during Amarillo Sheriff Helicopter flight. Side not facing wind (right) exhibited scorching and 

torching of trees in post-fire imagery, and a high intensity crown fire during helicopter flight was observed.

Background: City of 

Amarillo, used by 

permission, overlays NIST
80

Figure 51 Defensive action locations and primary structure categorizations in North Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
81

Figure 52 Radar derived percent slope in North Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
82

Figure 53 Radar derived aspect in North Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
83

9.5 Structural Element Ignition Mechanisms

The fire in the North Lake Tanglewood Community damaged numerous fences, railroad 

tie retaining walls and

landscaping borders. 

Additionally, detached decks, 

firewood piles and other features 

were also damaged and 

destroyed. A detached 

secondary structure was 

destroyed at 105 Port-O-Call 

Drive. Based on the timing of 

the destruction of this feature 

and the chronology of first 

responder actions in the area, it 

is possible that embers from this 

secondary structure ignited the 

wood roof at 102 Port-O-Call 

Drive.

Some fences in the North Lake Tanglewood Community were only partially burned. An 

example is shown in Figure 54 of a partially destroyed fence at 100 Camino Alto Drive. 

The destruction of the fence was predominantly in the direction of the wind and 

topographic configuration as discussed in section 9.4 above, with partial damage in the 

opposite direction of the wind and topographic configuration. It is unknown if the fence 

extinguished on its own or if it was extinguished by first responder intervention.

A firewood pile directly adjacent to the residential structure at 100 Camino Alto was also 

ignited and specifically identified 

as being defended by first 

responders and moved away 

from the structure as shown in 

Figure 55. No damage other 

than scorching to the residential 

structure was identified. The 

brick siding as shown in Figure 

55, aided in protection of the 

structure from fire in the early 

stages of burning. 

A wooden bench was also 

damaged on the west side of 

Camino Alto and not specifically 

identified as defended. As 

shown in Figure 56, the bench 

was burned from the bottom with 

no associated scorching to the siding or the top of the bench. There was also green 

vegetation in the adjacent area as shown in Figure 56. This indicates there was relatively 

Figure 54 Partially destroyed fence at 100 Camino Alto, 

NIST photo. 

Figure 55 Defended firewood pile at 100 Camino Alto, NIST 

photo.
84

low exposure on this side of 

the building with the burning 

of the wooden bench likely 

caused by a low intensity 

ground fire. As discussed in 

section 9.4 above, the low 

exposure might have been a 

result of topographic 

configuration. 

A partially destroyed wood

fence was also recorded at 

114 Bayshore Drive as 

shown in Figure 57. As can 

be seen in Figure 57, the 

heat from the burning fence 

caused the vinyl soffit to 

melt. There was, however, no scorching or burning to the underlying wood part of the 

soffit. There were extensive defensive actions in this area and it is unknown if the 

burning fence was extinguished by first responders or extinguished without manual 

intervention. As can be seen in Figure 57, the burning fence also caused scorching of the 

brick siding.

9.6 Vegetative Element Ignition Mechanisms

Untreated vegetation in areas behind 140 to 

154 Port-O-Call Drive was a hazard, which 

first responders defended against, into the 

early morning hours of February 28. Fire 

spread from these occluded wildlands to 

Buffalo grass and then to vegetated hedge 

rows as shown in Figure 48 and Figure 58. 

This vegetation helped spread the fire to 105 

Port-0-Call Drive. This fire spread from 

vegetation ignited the secondary structure 

described above at 105 Port-O-Call Drive. 

The destroyed home at 102 Port-O-Call Drive

is thought to have spread embers to Buffalo 

grass at 113 Bayrock Circle as shown in 

Figure 48. This Buffalo grass was 

specifically described as extinguished by first 

responders. The burned Buffalo grass in the 

interior area described above and shown in 

Figure 58, again appeared to correspond to areas with less photosynthetically active 

vegetation as shown in pre-fire infrared imagery displayed in false color in Figure 59. 

Figure 56 Damaged wooden bench and burned and unburned 

vegetation on west side of 100 Camino Alto, NIST photo.

Figure 57 Partially destroyed wood fence, 

which caused scorching to brick siding 

and melting of vinyl soffit, NIST photo.
85

The greyer areas both in the interior portion of Port-O-Call Drive and other locations 

burned while redder areas, likely corresponding to vegetation treatments (water and/or 

nutrients), did not burn.

Figure 58 Burnt hedgerow and Buffalo grass that facilitated fire spread to destroyed secondary 

structure at 105 Port-O-Call Drive, NIST photo.
86

10.0 South Lake Tanglewood 

This section begins with a tabulation of the damage and destruction to structural elements 

in the South Lake Tanglewood Community. Additionally, fire direction generalized from 

field observations of directional scorching are presented. Fire timeline information 

portrayed is derived from radio logs and the Amarillo Sheriff Helicopter flight. 

This section also discusses fire behavior in the South Lake Tanglewood Community. 

Defensive actions conducted in the community along with defensive action structure 

categorizations are also described. Topographic characteristics are mapped and 

discussed. Finally, identified structural and vegetative element ignition mechanisms are 

detailed.

10.1 Damage Assessment, Fire Direction and Fire Timeline 

Figure 61 shows damage to structural elements from the Tanglewood Fire within the 

South Lake Tanglewood Community. There were two damaged residential structures, one 

Figure 59 Pre-fire false color imagery showing redder areas that did not burn along with brown to 

black areas that did burn. In some locations the fire perimeter ended where these red, 

photosynthetically active, areas began and interior, red, photosynthetically active areas did not 

burn.

Background: City of 

Amarillo, used by 

permission, overlays NIST
87

destroyed residential structure, and 12 residential structures with no damage. There was 

numerous damage to and destruction of combustible and linear features. A breakdown of 

damage to detached combustible features is shown in Table 20. Damage and destruction 

to linear features by length is shown in Table 21.

Figure 62 shows fire direction in the South Lake Tanglewood Community. Little is 

known about the behavior of the wildland fire in this area. The wildland fire front 

appeared to reach the wildlands behind 200 South Shore Drive sometime after 15:30. 

However, it is not known precisely when the wildland fire front reached the wildlands 

behind 122 to 140 South Shore Drive, but these areas were already burnt by 18:18, during 

the Amarillo Sheriff Helicopter flight. A ground image at 17:14 shows the wildlands 

around 4 Canyon Circle already burnt. Nonetheless, fire behavior in these wildlands 

continued into the night (February 27 to February 28), as described by first responders. 

Exact fire direction in these wildlands was difficult to determine in the field.

There was only one location where the fire jumped South Shore Drive, which was on the 

west side of 109 South Shore Drive, as shown in Figure 62, though other embers might 

have jumped South Shore Drive and been suppressed by first responders before any 

ignitions could occur. The time of this fire jump is not known, illustrating one of 

multiple gaps in the fire timeline. The destroyed secondary structure was shown as 

igniting the one destroyed residential structure at 136 South Shore Drive at 18:16 during 

the Amarillo Sheriff Helicopter flight when the secondary structure was fully involved. 

There was a pile of unknown combustibles at 109 South Shore that was shown as fully 

involved during this flight also. Finally, a railroad tie retaining wall at 140 South Shore 

Drive was also shown as fully involved at 18:16. 

Table 20 Damage and destruction to detached combustibles in South Lake Tanglewood Community.

Combustible Feature Number Damaged Number Destroyed

Railroad Tie Retaining Wall 0 1

Deck 1 0

Hot Tub 0 1

Secondary Structures 1 1

Pergola/Gazebo 1 0

Playground Equipment 2 7

Boats 0 3

Lawn Furniture 0 1

Trailers 5 0

Grills 2 0

Dustbin 1 0

HVAC System 1 0

Electrical Utilities 1 0

Planters 1 0

Dog House 1 0

Unknown Combustible 0 1

Propane Tank 1 0
88

10.2 Defensive Action Categorizations

Figure 63 shows locations of identified defensive actions along with the resulting 

categorization of structures as to a defended category. First responders extinguished 

wood fences, railroad tie retaining walls, secondary structures, hot spots in the wildlands, 

residential grasses and various debris piles. Railroad tie retaining walls and secondary 

structures directly adjacent to wildlands were defended numerous times by different first 

responder teams due to multiple re-ignitions. There was a railroad tie retaining wall 

around treated vegetation at 140 South Shore Drive that was explicitly identified as being 

defended many times. The log home at 140 South Shore Drive was also explicitly 

identified as being defended, and it is assumed the home was defended against ember 

spread from the railroad ties. Finally, 212 South Shore Drive was explicitly identified as 

having water sprayed on it.

Table 21 Damage and destruction to linear features in South Lake Tanglewood Community.

Linear Feature Meters Damaged Meters Destroyed

Fence 18.6 (61 ft) 19.8 (65 ft)

Retaining Wall 286.6 (940 ft) 15.9 (52 ft)

There was residential grass around 200 South Shore Drive that was explicitly identified 

as being defended. The fire that destroyed the home at 136 South Shore Drive was 

contained by first responders. Destroyed features at 151 South Shore Drive were not 

explicitly identified as defended but it is possible the fire spread in this location was 

stopped by first responders. Extinguishment of vegetation along the east side of South 

Shore Drive also appeared to stop fire spread to 113 South Shore Drive and adjacent 

locations. Table 22 identifies damaged and destroyed linear and combustible features by 

identified defensive actions. 

10.3 Topographic Information

Figure 64 displays radar derived percent slope for the South Lake Tanglewood 

Community. Figure 65 portrays radar derived aspect for the South Lake Tanglewood 

Community. As with the Southern Palisades Community the fire appeared to enter some

sections of the South Lake Tanglewood Community in areas lacking cliffs. The damaged 

secondary structure at 200 South Shore Drive appeared to be a result of direct flame 

contact from burning vegetation, and the topography shown in Figure 64 displays an area 

between 160 and 200 South Shore Drive of moderate slopes. This area had continuous 

burned vegetation from the plateau right to the secondary structure. Vegetation in the 

steeper areas (i.e., cliffs) directly behind 160 and 212 South Shore Drive was not burned.

Table 22 Damage and destruction to features in South Lake Tanglewood Community categorized by 

identified defensive actions.

Feature Number 

Damaged/Destroyed

Number Identified as 

Defended

Linear Feature 24 7

Detached Combustible Features 23 2
89

It was more difficult in other locations in South Lake Tanglewood to identify paths of fire 

spread from the plateau into the canyons. There were areas of moderate slopes above 136 

South Shore Drive where the fire might have traveled. These areas of moderate slopes 

might have resulted in ignition of the secondary structure at 136 South Shore Drive, 

which was directly adjacent to burned wildlands. These moderately sloped areas might 

also have resulted in burning of the railroad tie retaining walls at 140 South Shore Drive. 

It is possible, however, that fire traveled through wildlands along South Shore Drive, 

having entered the canyon in the eastern most canyon described in Section 7.2. The 

available data for this location lacks the resolution necessary to determine the exact fire 

spread paths. 

10.4 Structural and Vegetative Element Ignition Mechanisms

The majority of structure ignition mechanisms found in the South Lake Tanglewood 

Community have been described above. Additionally, a wood pergola at 151 South 

Shore Drive had the roof ignited, as shown in Figure 60. This pergola was 12.5 m (41 ft)

away from the closest burned feature, which was wildland vegetation. A small retaining 

wall and telephone poles also ignited at 151 South Shore Drive, with the closest burning 

feature being 11.5 m (38 ft) away. The source of ignition of the above features had to 

have been embers due to unburned features all around and a road between these features

and other burned features. However, the embers could have come from another feature 

farther away than the distances listed above. Embers also caused melting of planters, a 

dog house and a trampoline at 128 South Shore Drive. The melting of these features did 

not appear to cause any significant flaming or radiant heat. 

As with other areas described above, the burning of residential grass in the South Lake 

Tanglewood Community appeared to coincide with areas that were not as red in infrared 

imagery, displayed as a false color composite compared to other areas that did not burn. 

This might be due to vegetation 

treatment. Many of the homes on 

the lake side of South Shore Drive, 

which did not have any burned 

features, appeared bright red in prefire imagery. It should, however, 

be noted that the exact extent of all 

defensive actions along South 

Shore Drive have not been 

quantified and some embers might 

have been suppressed by first 

responders before ignitions could 

occur.

Figure 60 Damaged pergola roof ignited by 

embers, NIST photo.
90

Figure 61 Damage to structural elements in the South Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
91

Figure 62 Fire direction and fire timeline in South Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
92

Figure 63 Defensive action locations and primary structure categorizations in South Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
93

Figure 64 Radar derived percent slope in South Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
94

Figure 65 Radar derived aspect in South Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
95

11.0 Southeast Lake Tanglewood 

This section begins with a tabulation of the damage and destruction to structural elements 

in the Southeastern Lake Tanglewood Community. Additionally, fire direction 

generalized from field observations of directional scorching are presented. Fire timeline 

information portrayed is derived from the Amarillo Sheriff Helicopter flight. Defensive 

actions conducted in the community along with defensive action structure categorizations 

are also described. Topographic characteristics are mapped and discussed. 

11.1 Damage Assessment, Fire Direction and Fire Timeline 

Figure 66 shows damage to structural elements from the Tanglewood Fire within the 

Southeast Lake Tanglewood Community. No residential structures were damaged or 

destroyed in this area. Damage and destruction did occur to some detached combustibles

and linear features as shown in Table 23. Damage and destruction to linear features by

length is shown in Table 24. The exact time of when most of the detached combustibles 

burned is not known. Figure 67 shows fire direction in the Southeast Lake Tanglewood 

Community. The fire jumped the circular driveway at 310 South Shore Drive in two 

locations. As listed in Figure 67, the fire in the wildlands moved through the area 

sometime prior to 18:21 on February 27. 

Table 23 Damage and destruction to detached combustibles in Southeast Lake Tanglewood.

Combustible Feature Number Damaged Number Destroyed

Short Fence 1 0

Short Retaining Wall 1 0

Brush Piles 0 2

Trailer 1 0

Mailbox 1 0

Table 24 Damage and destruction to linear features in Southeast Lake Tanglewood Community.

Linear Feature Meters Damaged Meters Destroyed

Retaining Wall 41 (134 ft) 0

11.2 Defensive Action Categorization

Figure 68 shows the locations of identified defensive actions along with the resulting 

categorization of structures as to a defended category. First responders extinguished 

railroad tie retaining walls, landscape borders, grass vegetation by South Shore Drive and 

also suppressed burning wildland vegetation to the west of the residential structures. The 

damaged combustibles by 310 South Shore Drive were not explicitly identified as 

defended, but the scorching of these features was minor and suppression of nearby 

burning vegetation by first responders might have alleviated some of the damage to these 

features. Table 25 identifies damaged and destroyed linear and combustible features by 

identified defensive actions. 
96

Table 25 Damage and destruction to features in Southeast Lake Tanglewood Community categorized 

by identified defensive actions.

Feature Number 

Damaged/Destroyed

Number Identified 

as Defended

Linear Feature 9 2

Detached Combustible Features 8 0

11.3 Topographic Information

Figure 69 displays radar derived percent slope for the Southeast Lake Tanglewood 

Community. Figure 70 portrays radar derived aspect for the Southeast Lake Tanglewood 

Community. As with other areas described above fire behavior was more heavily 

concentrated on one side of the canyon than the other side. It was more difficult to 

discern the precise area where the fire traveled from the plateau to the canyon in this area. 

Nonetheless, steep areas with cliffs have burned vegetation up to the cliffs on the plateau 

side with green vegetation on the canyon side of the community not being burned.

The residential structure at 314 South Shore Drive was also terraced above the 

surrounding wildlands. The terraced area, typically extending less than 20 m from the 

structure, consisted of treated residential grass, which did not burn except in one small 

location directly adjacent to the wildlands. The terracing as with 400 Casino Drive, 

might have helped direct fire behavior away from the house. As with other locations, 

however, it is unknown the exact role first responders played in preventing ignitions of 

the residential grasses on the terraced portion of 314 South Shore Drive.

11.4 Structural and Vegetative Element Ignition Mechanisms.

Other than the information shown in Table 23 and Table 24, not much is known about 

structural element ignition mechanisms in this area of the fire. Other than what is listed 

in section 11.3 above, not much is known about vegetative element ignition mechanisms 

in this area of the fire.
97

Figure 66 Damage to structural elements in the Southeast Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
98

Figure 67 Fire direction in Southeast Lake Tanglewood Community. The main fire front moved through area by 18:21 on 2/27/2011 based on Amarillo 

Sheriff Helicopter flight.

Background: City of 

Amarillo, used by 

permission, overlays NIST
99

Figure 68 Southeast Lake Tanglewood Community defensive action locations and primary structure categorizations.

Background: City of 

Amarillo, used by 

permission, overlays NIST
100

Figure 69 Radar derived percent slope in Southeast Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
101

Figure 70 Radar derived aspect in Southeast Lake Tanglewood Community.

Background: City of 

Amarillo, used by 

permission, overlays NIST
102

12.0 WUI Assessment Methodology and Science

WUI Assessment Methodology and Science are in their infancy. This study represents 

the first attempt at characterizing the entire fire disturbance continuum1in a post-fire 

environment. Although an original objective was to characterize all aspects of the fire 

disturbance, this study was not successful because the data was limited in resolution and 

completeness. This section addresses successes as well as shortcomings involved with 

assessing various aspects of the fire disturbance continuum. Additionally, possible 

improvements for future WUI assessments are listed. Recommendations for specific 

improvements to the NIST WUI 2 Data Collection System are listed in Appendix G. 

12.1 Pre-fire Hazard Mitigation Guidance and Assessment

Appendix H shows one field form from a pre-fire assessment of the Tanglewood Fire 

area, which occurred on some unknown date prior to the Tanglewood Fire. The data was 

not in electronic format, nor complete for the entire community, and could not be used in 

this assessment. However, if collected properly, pre-fire WUI assessment data might be 

used to assess the appropriateness of the respective WUI mitigation guidance under 

consideration, in context of a WUI post-fire environment. Pre-fire mapping of the WUI 

provides the possibility of adaptive management regarding current WUI mitigation 

guidance. Collection of pre-fire conditions and assessment of these conditions in a postfire environment would allow WUI mitigation guidance to be improved and enhanced. 

Nonetheless, the form presented in Appendix H highlights the need for a paradigm shift

regarding WUI mitigation guidance. Most WUI mitigation guidance is presented to users 

in the form of weighted assessments. Each attribute collected has a specific weight 

assigned to it with the cumulative weighted attributes representing a total score for the 

property being assessed. These weighted WUI assessment methods have the possibility 

of presenting the homeowner with a false sense of security and preparation. There are no 

science-based WUI mitigation methods which take into account the spatial relationship 

amongst and between all WUI features, and rate WUI mitigation actions accordingly.

Although distance to features is often considered, linear distance does not necessarily 

capture the full exposure from a dangerous topographic feature that has consequences for 

a structure’s susceptibility to destruction from wildland fire. The interaction must include

the spatial configuration of that topographic feature in relation to the structure, fuels and 

the wind. Some topographic features are not always dangerous in context of a WUI fire, 

such as cliffs or terraced platforms, which might serve to protect a structure in certain 

spatial configurations as described above. However, these features might direct fire to 

other structures or properties. 

WUI mitigation guidance, presented in the form of weighted attributes, could result in 

homeowners working towards achievement of low scores for some treatments while 

leaving other more relevant attributes alone. Take for example 334 Cactus Drive, 

described above. This home had many features that would have resulted in low weighted

scores in many WUI Mitigation models. The home had a metal roof, siding was largely 

brick (with some minor wood) and there was treatment 9 m (30 ft) around the structure. 

However, the Tanglewood Fire highlighted the vulnerability of combustible secondary 
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structures, which were contained by first responders, close to the residential structure. 

This single attribute, which is not accounted for in many WUI Mitigation guidance (i.e., 

secondary structures and spatial relationship to residential structure), could have been 

ignored and still resulted in an “acceptable” score for the property, leaving the 

homeowner blissfully unaware of the potential hazard on their property. 

A better approach, given the current understanding of the WUI and wildland fire, would 

be to identify hazards and not weight particular attributes. As WUI fire science

progresses to a better understanding of the spatial relationships among WUI features, the 

framework5can be coupled with implementation, using the concepts of Geodesign15,

might result in more effective WUI mitigation advice than what currently exists. In the 

interim, mapping of existing hazards in WUI communities without the use of unfounded 

weighted attributes would provide a means of identification for homeowners and first 

responders of existing hazards (manmade and natural), thereby providing potential for 

removal of hazards by homeowners and land managers, and recognition by first 

responders during fires.

12.2 Pre-Fire and Post-Fire Landscaping Characteristics 

This study did not focus on assessment of landscaping characteristics. Information was 

collected during the post-fire assessment on irrigation conditions and continuous fuels in 

various treatment zones around residential structures. While collecting vegetative data, a 

number of technical issues were identified. Five examples are provided here, while 

improvements to the WUI 2 data collection method are listed in Appendix G.

1. The data collection system asked if, for each treatment zone, irrigation was present. 

Some data collectors interpreted this to assess if irrigation was present during the fire. 

Additionally, because vegetation was in senescence, it was difficult to determine 

irrigation conditions at the time of data collection. 

2. Assessing landscaping characteristics on properties that had burned vegetation can 

lead to a bias assessment of landscaping characteristics. 

3. Information was collected on burned vegetation, but again, there was difficulty with 

consistent interpretation by data collectors. 

4. The delineation of burned vegetation in the field by data collectors varied greatly due 

to problems with provided definitions and guidance.

5. There was no assessment of conditions present in the wildlands.

Assessment of landscaping characteristics, residential or wildland, in context of a postfire assessment requires having details on these characteristics in a pre-fire environment. 

These details should be collected at a sufficient temporal resolution (every one to two 

years, though this might be site dependent) to result in relevant conditions at the time of 

the fire being portrayed. Nonetheless, post-fire vegetation information also needs to be 

collected.

Field data collection of burned vegetation is a key component of post-fire assessments. 

This field data collection, however, must be coupled with timely acquisition of aerial 

imagery of sufficient spatial resolution, and focus on detailed ground imaging. The postfire imagery provided by the City of Amarillo was essential to this assessment, but the 

temporal resolution after the fire (i.e., 30 days) resulted in some burned vegetation being 
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difficult to identify. For example, Figure 71A shows an image of burned vegetation right 

after the fire, while Figure 71B shows an image of the same area from the City of 

Amarillo provided post-fire imagery. As can be seen, the black marks, which clearly 

identify the burned area in the imagery right after the fire (Figure 71A), are not present in 

the aerial imagery taken a month later (Figure 71B).

Figure 71 A: Image of burned vegetation right after the main fire front moved through the area. 

B: Aerial image of same area acquired one month after fire, lacking clear black demarcation of 

burned area.

Remote sensing, combined with field assessments, presents the best means to obtain prefire and post-fire vegetation information, as aerial imagery and LiDAR lacks the ability to 

identify understory conditions for both pre-fire and post-fire conditions. Advances in 

remote sensing have resulted in the timely acquisition of high spatial resolution imagery 

for most locations. This study site did have four-band imagery acquired in 2009. 

Additionally, post-fire response imagery acquired to assess response of vegetation can 

help to provide additional important information. For example, Google Earth Imagery 

acquired a year after the fire was used to help identify locations where the fire did, and 

did not, enter canyons based on vegetation green up.

Aerial imagery, however, does lack the ability to identify understory conditions (even 

LiDAR data will vary in its ability to identify understory conditions) for both pre-fire and 

post-fire conditions. Consequently, homeowners living in the WUI should be encouraged 

to photograph their landscapes in the same manner they are encouraged to photograph 

their personal belongings. Technologies such as PhotosynthTM, and structure from 

motion, might provide potential for detailed pre-fire imaging of WUI understory 

conditions. Pre-fire WUI mitigation advice should also involve ground sampling of 

wildlands in close proximity to residential structures using established plot based 

techniques such as the Forest Inventory and Analysis National Program, the Fire Effects 

Monitoring and Inventory Protocol, or some other appropriate protocol. Homeowners 

should also be careful of listing these images publicly as they can be used for nefarious 

purposes by others.

Post-fire field data collection of burned vegetation should focus on imaging the burned 

vegetation on the ground with collection of very simple attribute information about 

directional scorching, scorch heights, white ash accumulation, char depth, and possibly 

other factors. Collection of this information should not be limited to residential areas and 

should continue into wildlands. A post-fire data collection methodology to estimate 

vegetative fuel consumption is needed. This ground information should be coupled with 

A B

Background: City of 

Amarillo, used by 

permission, overlays NIST

Photo NIST
105

timely acquisition of aerial and ground imagery. Studies need to be conducted to 

determine degradation of information with increased time of acquisition after the fire in 

regards to aerial imagery. 

The collection of post fire vegetation data from residential parcels, together with remote 

sensing for both pre and post fire documentation, has provided significant insights on 

improving future WUI vegetative data collection. Additionally, the collected information 

provided valuable insights, as described in Sections 5 through 11, in evaluating fire 

behavior around many structures within the fire perimeter. 

12.3 Building Characteristics 

A focus of the data collection effort utilized for this study was on the assessment of 

building characteristics. Out of the 183 structures documented in this case study, 35

homes were destroyed, and 13 were damaged. An unprecedented amount of structural 

elements were collected in the field and updated in the office using pre-fire and post-fire 

remote sensing. This included association of images of many of these structural elements 

to spatial locations, resulting in a unique spatial database in the WUI. Additionally, 

collection of this detailed structure information allowed for identification of numerous 

ignition mechanisms as detailed above. It should, however, be noted that analysis is 

confined to those structural treatments for which information exists prior to the fire. This 

information typically only exists, as was the case in this study, in local tax assessor’s 

databases. Analyzing the response of destroyed structural elements is extremely difficult 

without the necessary pre-fire construction information, and prone to errors.

The data collected during this deployment, together with existing pre-fire information, 

was used to qualitatively evaluate individual structural response. When this was 

accomplished, it was done in context with known local exposure conditions and 

defensive actions. It was determined that damaged structures were preferable for analysis 

compared to destroyed structures, as building materials identification was more reliably 

achieved. 

It should be noted, however, that even when pre-fire data exists, there are additional 

technical issues that need to be resolved before explicit statements about building 

material response can be made. For example, the destruction of a home with a wood roof 

does not mean the wood roof was the cause of the destruction. A wood deck, nearby 

secondary structure, or other factor might have ultimately contributed to the destruction. 

Without eyewitness accounts of the destruction, it is basically impossible to determine.

Nonetheless, in certain circumstances, analysis of certain building treatments might be 

possible, particularly in regards to identifying areas where current WUI mitigation advice 

is wrong (e.g. wood roofs are the major structural attribute problem in the WUI). This 

analysis, however, would still require, prior to the destruction by fire, knowledge of the 

building treatments. As mentioned above, this information would typically be obtained 

from local tax assessors. This highlights the need, in some locations, for expanded data 

collection in WUI areas prior to the fire regarding a plethora of building treatments 

including secondary structure information, attached combustibles, window treatments and 

other factors. Collection of this type of information varies greatly across the United 
106

States. A summary of some of the data collected is listed in Appendix F. The data 

presented is for attributes that were determined/known for many of the destroyed homes.

In the context of post-fire assessments, while it is important to document all the damage 

occurring in the area, characterization of all the structural elements is an onerous and 

unnecessary task when extensive pre-fire data is available. In addition to focusing on 

documentation of damage and destruction to all structural attributes, post-fire 

assessments should focus on structural treatments that might provide pertinent 

information for the given study and for which pre-fire information exists. This would be 

incident dependent. Post-fire assessments can then collect subsets of the structural 

information for undamaged buildings to assess the accuracy of the pre-fire structure 

information being used for the respective study. This type of information, when used in 

combination with defensive actions and exposure information as part of a detailed 

timeline reconstruction, is necessary to assess building attributes response. 

12.4 Topographic Characteristics 

Unlike building and landscaping characteristics, topographic characteristics can be 

collected either pre-fire or post-fire, with most topographic characteristics not changing 

substantially over time. This study did attempt to assess topographic characteristics in 

the field. The use of radar data did help to provide consistent topographic information 

across the study area, however, the available radar data lacked the spatial resolution of 

the LiDAR data used successfully during the Witch/Guejito fire case study.

9

 A number 

of topographical data collection improvements were identified to improve the data quality 

for future studies. Recommended data collection improvements are listed in Appendix G.

The use of digital elevation models for the assessment of topography is superior to field 

data collection techniques, short of actual surveys, because it provides a more consistent 

interpretation. It is not known, however, the resolution at which topographic information 

is required. It is possible that the scale of fire behavior is dependent to some extent on 

the scale of topography, with micro-topographical features in the range of meters 

affecting fire behavior over the same distances. For example, at the Trails at Rancho 

Bernardo Community studied by Maranghides et al,

9

topographic features were at a 

coarser scale (on the order of tens of meters) than those at the Tanglewood Canyon 

Communities. It is, therefore, likely that the radar data did not capture all pertinent 

topographic features in this study, which had consequences for understanding and/or 

characterizing fire behavior.

The Trails at Rancho Bernardo Community provided an opportunity to examine the 

required spatial resolution of topography for post-fire assessments because high 

resolution topographic data does exist.

9

 The same analyses conducted by Maranghides et 

al9could be run with radar data and 10 m (33 ft) United States Geologic Survey (USGS) 

Digital Elevation Models (DEMs) and examine differences. This also highlights the need 

for validated physics based fire models capable of providing a better understanding of 

appropriate scales for assessing and analyzing WUI environments.
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12.5 Defensive Actions and Fire Behavior

Defensive actions play a critical role in reconstructing WUI fire events as the state of the 

post fire environment is directly tied to them. Table 26 contains specifics on the homes 

damaged with respect to location of damage and associated defensive actions. The data 

show that 11 damaged homes out of the 13 damaged homes had evidence of defensive 

actions and out of the 11 that were known to be defended, the defensive actions on 5

exactly match the damage that was recorded. 

Table 26 Damaged structures with damage status and defensive action.

Address Damaged Status Defended

450 Casino Drive

Attached Carport (No 

Damage to Main Building) No Actions Identified

411 Roberts Drive Deck and Siding

Deck and Siding Identified as 

Defended

585 Canyon Creek Drive Stairs Stairs Identified as Defended

144 Exmoor Road

Deck (No Damage to Main 

Building) Deck Identified as Defended

475 Casino Drive

Discoloration on House; 

Damage to Attached Fence

Not Specifically Identified as 

Defended but Signs of Defensive 

Actions

105 Port o Call Drive Attached Deck and Fence

Deck and Fence Identified as 

Defended

102 Gary Drive

Damage to Eave in Two 

Separate Locations, Broken 

Window, Scorching of Brick Eave Damage Identified as Defended

114 Bayshore Drive

Melted Eaves, Possibly 

Broken Window,Scorched 

Siding, Completely Destroyed 

Fence and Deck

Defensive Actions Identified but 

Fence and Deck Not Specifically 

Identified and Completely 

Combusted

1 Canyon Circle Minor Scorching Damage Property Identified as Defended

4 Canyon Circle

Minor Window Damage; 

Damage to Fence Property Identified as Defended

400 Casino Drive Melted Eave

Eave Not Specifically Identified as 

Defended

124 Saint Andrews 

Road Scorched Siding Specifically Identified as Defended

140 Bayshore Drive Scorched Siding Specifically Identified as Defended

An analysis of the fire scene without full knowledge of defensive actions or the lack 

thereof can be very misleading, as demonstrated in Section 8.5. Additionally, defensive 

actions can provide critical insight into fire behavior, exposure and local weather 

conditions as well as interactions between these four different components of WUI fires.

In this incident, defensive action information was collected and evaluated for the first 

twelve hours after ignition. Out of the 183 structures in the study domain 82 (45%) were 

identified as having been defended during the fire. Defensive actions information along 

with fire and weather observations, still images and video, enabled the event 
108

reconstruction. In evaluating the effectiveness and efficiency of the data collection part of 

the methodology, a number of possible improvements were identified and are listed in 

Appendix D.

In order to fully utilize defensive action information, it is necessary to have a better 

understanding of the timeline of the fire and when defensive actions occurred. In this 

incident, first responder time estimates were difficult to reconcile. This is logical as it is 

not the first responder’s responsibility to know the precise time of when and where 

certain events occurred. Additionally, possibly due to the high stress environment of any 

WUI fire event, times might become distorted for first responders. Nonetheless, most 

first responder accounts did correspond to observed features on the ground or at worst, 

close by features observed on the ground, allowing for the identification of many 

defensive action locations though not always the exact times these actions occurred.

The solution to effectively capture the sequencing and timing of defensive actions resides 

in large part in technological solutions and the implementation of documentation 

protocols. Relatively recent technologies like automated vehicle location systems, mobile 

phones, global positioning systems (GPS) and imaging technologies like GoProTM, allow 

for recording of real time fire information to help better understand the fire timeline. 

More widespread adoption of these technologies could not only allow for better 

understanding of WUI events, but also provide valuable information to first responders to 

improve tactics and firefighting efficiency for both wildland and structural fires. 

There appears to be a wide range of fire department guidance on how to handle images 

from incidents, with some departments being against collecting imagery while others 

supporting it in various ways. Real time images and video are critical event timeline

reconstruction tools and in many cases provide the critical information needed to quantify 

fire behavior and structural response. There is a lack of clear guidance provided to first 

responders for documenting incidents in real time, as well as collecting, sorting and 

storing incident images and video. 

Implementation of the above technologies with timely post-fire aerial and ground 

imagery would also help to understand fire behavior. To the extent practical, flights such 

as the Amarillo Sheriff Helicopter flight or the utilization of unmanned aerial systems 

(UAS) when regulations allow, can also provide valuable fire behavior information. 

Sensing of high intensity fire behavior, however, will always be difficult from the air and 

use of direct ground sensors would be preferable. This would be necessary not only for 

quantifying heat fluxes but also for the quantification of ember fluxes. 

Quantification of heat fluxes has been demonstrated in a number of prescribed burns 

including the International Crown Fire Experiments,

16 Pine Barren Research Burns17 and 

Bastrop Research Burns.

18

 Ember flux quantification research from wildland and 

residential fuels had been very limited, while a very limited of total ember exposure data 

has been collected.

19 The Joint Fire Science Program is beginning to address this 

deficiency with the FY2015 Solicitation on embers research.

20

 
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The three NIST WUI case studies9, 10, 11 to date have been conducted at the Wildland 

Urban Interfacek. The studies provide a very preliminary understanding of the key drivers 

of fire behavior and defensive actions. There have been no such studies at the intermix.

12.6 Fire Weather 

Field indicators such as needle freeze and tree scorching were used as surrogates for fire 

behavior and local wind. While only a limited number of sensor locations provided 

quantitative weather data, post fire field observations together with first responder 

observations enabled a general understanding of the complexities of local weather 

particularly when coupled with the complex topography of the Tanglewood Complex 

Fire. The multidirectional fire behavior indicators in Figure 38 illustrate the complexities 

of characterizing fire behavior without information of wind and a preliminary 

understanding of general event timeline. The almost contradicting fire behavior from 

field data illustrated in Figure 38 demonstrates that additional technical understanding is 

necessary to quantify wind flow through topographically complex communities and that 

the coupling of wind and fire behavior needs to be further characterized. 

NIST is conducting work to characterize wind flow though topographically complex

terrain. San Diego State University is conducting a long term wind flow study at the 

Trails community in Rancho Bernardo, California.

21 This community, which was affected 

by the Witch and Guejito fires in 2007, is being instrumented to capture wind behavior in 

different wind conditions including during Santa Ana winds. The collected wind flow 

data together with the post-fire field data, will be used to improve the technical 

understanding of fire behavior through the community during the 2007 fires. Collecting 

wind data in complex communities across the Trails is the first step to improve the 

technical understanding of fire behavior through the community during the 2007 fires.

Additionally, wind data from this community will be used to assess large domain fire 

behavior prediction models such as the USFS Wildland Fire Dynamics Simulator22 or the 

NIST Fire Dynamics Simulator.

23

12.7 Exposure Characterization 

The post-fire WUI environment poses significant challenges in qualifying fire and ember 

exposures. The post-fire scene represents the final product of the interactions between 

exposure, defensive actions and the response of fuels (vegetative or urban) to the actual 

exposure. The exposure itself is a function of fuels, topography and the local weather. To 

further complicate the scene, the exposure, defensive action and weather can vary with 

time. As described earlier in the report, at any one location there can be numerous fire 

fronts, wind shifts and multiple defensive actions all taking place at different times. 

A detailed timeline reconstruction, along with detailed weather and defensive action 

information, together with pre-fire conditions, are all necessary to begin qualifying 

exposure. The complexities of collecting all the above mentioned data with sufficient 

temporal and spatial resolution make the quantification of exposure in the fire 

environment practically impossible. There is, however, great value in a qualitative 

 

k The report on the third NIST case study of the Waldo Fire is being finalized and has not yet been 

published. 
110

assessment of exposure, as this information can be used, to first order, to determine how 

the event developed, and which homes were exposed to fire and embers and which homes 

were not. The information collected can be used to assess hazard mitigation technology 

failures rather than to quantify a success, which in the absence of field instrumentation

can be very misleading and possibly lead to a false sense of security by homeowners.

In a post-fire environment, it may be possible to say that given current building materials 

and construction, a given structure separation distance may not be sufficient to prevent 

structure to structure direct flame impingement under certain topographical and weather 

conditions. However, post-fire reconstructions may offer only limited value in providing 

the exact spacing necessary to prevent ignition of a specific construction material under 

specific conditions. This is due to the finite number of data points and more specifically, 

due to the frequent interventions of first responders which effect the effective exposure of 

the structure.

Detailed exposure characterization is best accomplished in a controlled environment in 

real scale. Using prescribed burns, data can be collected on both fire and ember exposures

under low to moderate exposure conditions. This experimental work will need to be 

conducted in different categories of vegetative fuels5and under different topographic and 

weather conditions. The information collected would then be used to further develop 

reliable fire behavior prediction models. These models or tools could then be used to 

predict heat and ember fluxes in more extreme conditions. This information could be 

augmented, once appropriate data collection methodologies are developed and tested, by 

collecting data from real fires both in the wildlands and the WUI.

Additionally, quantification of the pre-fire, during-fire and post-fire environment of 

prescribed burns might lead to the discovery of surrogates that might be used to provide a 

better understanding of exposure in both wildland and WUI environments. Several 

surrogates such as white ash accumulation, scorching, leaf and needle drop and others 

might provide valuable surrogates for post-fire exposure assessment. 

13.0 Technical Findings Summary

The five primary findings are listed here:

1. Information collected from detailed post-fire case studies is more useful for assessing 

hazard mitigation technology failures than for quantifying successes (data collection 

and analysis methodologies).

2. Damaged structures provided more useful information compared to destroyed 

structures, as building materials and ignition location were more reliably identified 

(structure ignition and hazard mitigation).

3. Damaged structures, which were defended, in many cases did not show direct signs of 

defensive actions. Without the collection of defensive action data, the effectiveness of 

hazard treatments can be wrongly interpreted (defensive actions).

4. Remote sensing combined with field assessments presents the best means to obtain 

pre-fire and post-fire vegetation information (data collection and analysis 

methodologies).
111

5. Mapping of existing hazards in WUI communities without the use of weighted 

attributeslprovides a means for identification of existing hazards (manmade and 

natural). This will provide potential for removal of hazards by homeowners and land 

managers, and recognition by first responders during fires (structure ignition and 

hazard mitigation). 

The specific findings on structure ignition and hazard mitigation areas include: 

1. Out of the 183 structures documented in this case study, 35 homes were destroyed, 

and 13 were damaged.

2. Secondary structures such as sheds, garages, etc., when ignited, generated a 

significant amount of embers, exposing primary residences under certain conditions 

to increased hazardous conditions.

3. Mapping of existing hazards in WUI communities without the use of weighted 

attributes provides a means of identification of existing hazards (manmade and 

natural), thereby providing potential for removal of hazards by homeowners and land 

managers, and recognition by first responders during fires. 

4. Ember and fire generating combustibles, both detached and attached to residential 

structures, include fences, decks, railroad ties, mulch beds, attached stairs and piles of 

firewood.

5. Detached combustibles, in numerous cases, ignited prior to the primary structure and 

were then responsible for the ignition of the structure.

6. Damaged structures, which were defended, in many cases did not show direct signs of 

defensive actions. Without evidence and documentation of defensive action data, the 

effectiveness of hazard treatments can be wrongly interpreted.

7. The exposure from a fire burning up to or near a structure varied significantly across 

the incident. In some cases, a very low intensity fire reached the structure walls, while 

in other cases very severe fire exposure was experienced by the structure even 

without fuel reaching all the way to the structure walls.

The findings on defensive actions include:

8. Out of the 183 structures in the study, 82 (45%) were identified through technical 

discussions as having been defended during the fire.

9. The lack of evidence of a defensive action around a particular structure or feature 

does not mean that a defensive action did not occur on that feature. This implies that 

due diligence in collecting data from first responders is necessary.

10. Same as technical finding #6 (above).

11. Many features including fences and railroad ties were recorded as being defended 

multiple times by different first responders. This is consistent with the features’ long 

lasting potential to generate flames and embers. These items increased the hazard to 

nearby unburned structures.

12. Relatively recent technologies such as AVL systems, mobile phones, GPS and 

imaging technologies allow for recording of real time fire information that could help 

better understand fire timeline information. 

 

l Current WUI Fire hazard rating systems rely on very limited technical information to develop weighted 

ratings. Due to this limited technical information such weighed systems can provide erroneous assessments 

of actual hazards.
112

The findings on exposure and fire behavior include:

13. Fire moved from the fire origin, in the vicinity of 501 Pinto Drive, and crossed Cactus 

Road into the wildlands to the east of Timber Creek Canyon (a linear distance of 

approximately 500 m (1640 ft.)) in about 30 min or less. 

14. The post-fire scene represents the final product of the interactions between exposure, 

defensive actions and the response of fuels (vegetative or urban) to the actual 

received exposure. This was also identified in the Witch/Guejito case study.

15. Fire and ember exposure onto a target was a complex function of fuels, topography 

and the local weather. The interaction between topography and weather significantly 

affected local exposure conductions. Parcel aspect in combination with local 

prevailing winds sometimes had a significant impact on local exposure conditions.

16. The exposure, defensive actions, and weather vary with time. There were numerous 

fire fronts, wind shifts and multiple defensive actions all taking place at different 

times.

17. Fire burned more intensely along the leeward side of canyons and drainages.

18. Topographic features that significantly affected fire behavior were in many cases less 

than 40 m (130 ft) in length, such as terracing around a structure.

19. In numerous locations, steep slopes or cliffs appeared to stop fire spread in both the 

upward and downward directions. 

20. Fire direction observations from the field were misleading without utilizing a detailed 

event timeline, as multiple fire fronts or changes in wind direction occurred during 

the fire incident. 

The findings on data collection and analysis methodologies include:

21. Electronic data collection systems are essential in capturing the multidimensional data 

and interactions between topography, fuels, weather and defensive actions associated 

with WUI fires. 

22. Same as technical finding #14 (above).

23. Complexities of collecting field data with sufficient temporal and spatial resolution 

make the quantification of exposure in the post-fire environment difficult. There is, 

however, great value in a qualitative assessment of exposure as this information can 

be used, in first order, to determine how the event developed and which homes were 

exposed to significant fire and embers and which homes were not. 

24. Information collected from detailed post-fire case studies is more useful for assessing 

hazard mitigation technology failures than for quantifying successes. 

25. There is a lack of clear guidance provided to first responders for documenting 

incidents in real time, as well as collecting, sorting and storing incident images and 

video. 

26. Data collected on vegetation both for the wildlands and in the community were 

important to understand the fire behavior. 

27. There is currently no established post-fire data collection methodology to estimate 

vegetative fuel consumption. 

28. Remote sensing combined with field assessments presents the best means to obtain 

pre-fire and post-fire vegetation information, as aerial imagery and LiDAR lacks the 

ability to identify understory conditions for both pre-fire and post-fire conditions.
113

29. Post fire data loss based on aerial imagery increased with time of acquisition after the 

fire. 

30. Analysis of the effectiveness of structure treatments requires pre-fire data for 

comparison. This was also identified during the Witch/Guejito case study, NIST TN 

1635.

31. Many structure treatments could confound the analysis/interpretation of structure 

performance during a WUI fire. For example, the destruction of a home with a wood 

roof does not mean the wood roof was the cause of the destruction. Without 

eyewitness accounts of the destruction, it is impossible to determine the ignition 

sequence.

32. Damaged structures provided more useful information compared to destroyed 

structures, as building materials and ignition location were more reliably identified.

33. There are no case studies similar to this one at the Wildland Urban Intermix, resulting 

in very limited understanding of how to effectively implement mitigation techniques 

in that environment.

34. Currently, there is a no validated physics based fire model capable of providing a 

better understanding of appropriate scales for assessing and analyzing WUI 

environments.

14.0 Recommendations

As a result of this study, the following are the five primary technical recommendations:

1. Adequate technologies need to be developed and deployed to document the event 

including first responder actions. - Technical finding #12. 

2. The coupling of wind and fire behavior needs to be better characterized, including 

the quantification of wind flow through topographically complex communities. This 

is necessary in order to quantify fire behavior at the WUI - Technical finding #15. 

3. Standardized electronic data collection systems need to be implemented to capture 

post-fire data - Technical finding #21. 

4. Clear guidance need to be developed for first responders to document incidents in 

real time, as well as collect, sort and store incident images and video - Technical 

finding #25. 

5. Pre-fire WUI mitigation advice needs to involve vegetative sampling of wildlands in 

close proximity to residential structures using standardized plot based techniques -

Technical finding #26.

 

Additionally there are three recommendations that will improve community resilience to 

WUI fires by conducting specific research activities as well as data collection. These are:

1. Heat fluxes and ember fluxes from wildland and urban interface fuels need to be 

quantified in both wildfire and controlled environments - Technical finding #3.

2. A methodology needs be developed to estimate vegetative fuel consumption in a postfire environment. Collection of this information should not be limited to residential 

areas and should continue into the wildlands - Technical finding #27.

3. Case studies similar to this one need be conducted at the Wildland Urban Intermix –

Technical finding #33.
114

15.0 Conclusions

The Amarillo fires of 2011 was the first time the NIST WUI 1/WUI 2 field data 

collection methodology was utilized to investigate WUI fires. The method successfully 

documented the fire scene. A number of improvements have been identified as a result. 

These improvements will be implemented in future deployments. 

The Tanglewood Complex post-fire data collection and analysis resulted in a number of 

technical findings, including seven on structure ignition and hazard mitigation, five on 

defensive actions, eight on exposure and fire behavior, and fourteen on data collection 

and analysis. The technical findings identified in this case study are applicable at the 

interface between the wildlands and urban areas. The data collection and analysis 

findings will also apply at the Wildland Urban Intermix. Additionally there are six

general recommendations and two research recommendations that will improve 

community resilience to WUI fires. 

A very preliminary and limited data analysis was conducted in Section 13. This was due 

to limited resources as well as limited defensive action information and complex 

exposure conditions in many parts of the Tanglewood Complex Fire. These preliminary 

and limited findings indicate that additional analysis needs to be conducted in the future 

to assess the impact and contributions of different building attributes and topographical 

features such as aspect. Future WUI deployments should include case studies of both 

interface and intermix fires using the improved methodologies highlighted from the 

Amarillo fires documented and analyzed here. Deployments should be focused in 

locations/areas where there is reliable pre-fire data. Incidents with 100 to 400 destroyed 

homes represent a sizable data set that can yield important lessons learned. Entire 

incidents should be investigated, instead of a subset of a larger incident as, by looking at 

the entire incident, the entire response can be analyzed in context. Future case studies will 

continue to provide fire behavior, structural response/ignition vulnerabilities and 

defensive actions technical information that will continue to provide guidance for 

laboratory experiments, model development and large scale field research.

16.0 Acknowledgments 

The Joint Fire Science Program, Grant #11-1-3-29m is acknowledged for providing the 

half of the funding for this deployment, post-fire analysis and documentation. The Texas 

Forest Service and Coeur d’Alene Tribe are acknowledged for their assistance with data 

entry and data collection. The City of Amarillo and Potter-Randall County 911 are 

gratefully acknowledged for their extensive cooperation in providing vector and raster 

data for this analysis. The authors would also like to acknowledge the citizens of Timber 

Creek, Palisades, Tanglewood and Tangle Air and the first responders for their insights 

into the fire development and defensive actions taken. Additionally the authors would 

like to acknowledge Blaza Toman from NIST for conducting the statistical analysis 

presented in this report.

 

m JFSP 11-1-3-29, Evaluating the Effectiveness of Mitigations Activities in the Wildland Urban Interface.
115

Appendix A NIST TN1708 Preliminary Findings
116

The following preliminary findings relate to the two specific objectives of the initial 

reconnaissance:

Likely technical factors responsible for the damage, failure, and/or successful 

performance of buildings and/or infrastructure in the aftermath of the Amarillo fires

 Extreme weather, in the form of severe wind and very low humidity, resulted in very 

rapid fire spread.

 Buffalo grass, even when mowed, carried fire on residential yards and in the wild.

 Statewide pre-deployment of firefighting resources using the Texas Intrastate Fire 

Mutual Aid System (TIFMAS) was effective in rapidly getting resources to the fires.

 Extensive defensive actions were identified in the Tanglewood Complex fire. The 

defensive actions will be factored into the evaluation of the response of structures to 

the WUI fire in the detailed technical report.

 Certain foundation constructions (pier and beam), as well as modular/mobile homes 

may exhibit certain ignition vulnerabilities.

 Pre-fire and post-fire aerial imagery, particularly oblique imagery such as that found 

on MicrosoftTM Bing Maps, was found to be essential for efficient and accurate 

delineation of the total number of damaged/destroyed structures.

 The local wind direction and speed, and the topography, had a significant impact on 

fire behavior; however, limited weather observation equipment was located in the 

bottom of the canyon and along the creek beds.

Specific improvements to standards, codes, and practices as well as any further 

research and other appropriate actions based on study findings

 The multijurisdictional aspects of this event posed a significant challenge to the 

accurate documentation of the damage and performance of the buildings.

 In the absence of a national standardized data collection framework, the NISTdeveloped WUI 1 and WUI 2 systems enabled the documentation and analysis of 

structural loses from the Amarillo WUI fire.

 Collecting data from undamaged as well as from the damaged/destroyed structures 

provided for meaningful assessment of the data.

 There is no scale to characterize the severity of WUI events, like the scales used to 

rate tornadoes, hurricanes or earthquakes.

 Additional weather observational equipment in numerous locations in the bottom of 

the canyon and along the creek beds would significantly help NWS forecasters, and 

also help local fire officials understand the potential behavior of the fire. Additional 

Remote Automated Weather Stations (RAWS) or West Texas MesoNet stations 

would be extremely helpful in cases of wildfires in these areas.n

 

n From NWS Amarillo Office, email communication, March 28, 2011.
117

Appendix B Unassessed Building Characteristics
118

The data contained in this appendix illustrate the limitations of not having reliable prefire building construction information specifically in identifying attributes of the 

destroyed homes. The data shows that for eave construction material, 25 out of 28 

undetermined were destroyed homes. The same applies to eaves type where 24 out 25 

unknowns were destroyed homes and gutters where 20 out the 22 undetermined were 

destroyed. The same issue associated with undetermined construction applies to the rest 

of the tables in this appendix.

Table 27 Eave Material across Residential Structures

Eave Material Totals Damage (Attached 

Combustible) Destroyed Damage No Damage

Not Determined 28 0 25 0 3

Cement Fiber 6 0 0 0 6

Heavy Timber 1 0 0 0 1

Light Timber 98 3 3 7 85

Vinyl 11 1 0 2 8

Metal 13 0 0 0 13

Other 15 0 4 0 11

Not Applicable 11 0 3 0 8

Table 28 Eave Type across Residential Structures

Eaves Totals Damage (Attached 

Combustible) Destroyed Damage No Damage

Not Determined 25 0 24 0 1

Boxed 123 3 6 8 106

Exposed 24 1 1 1 21

99 11 0 4 0 7

Table 29 Gutter Material across Residential Structures

Gutter Material Totals Damage (Attached 

Combustible) Destroyed Damage No Damage

Not Determined 22 0 20 0 2

Combustible 7 0 1 0 6

NonCombustible62 1 9 3 49

Not Present 92 3 5 6 78
119

Table 30 Roof and Gutter Debris across Residential Structures

Roof/Gutter 

Debris Totals

Damage (Attached 

Combustible) Destroyed Damage No Damage

Not Present 102 3 2 4 93

Present 14 0 1 1 12

Not Applicable 28 1 1 4 22

Not Determined 39 0 31 0 8

Table 31 Shutter Material across Residential Structures

Shutter Material Totals Damage (Attached 

Combustible) Destroyed Damage No Damage

Not Determined 26 0 24 0 2

Combustible 13 0 0 2 11

Not Combustible 13 0 2 0 11

Not Present 131 4 9 7 111

Table 32 Window Frame Type across Residential Structures

Window Frame Totals

Damage (Attached 

Combustible) Destroyed Damage No Damage

Not Determined 21 0 19 0 2

Wood 20 1 4 1 14

Metal 137 3 12 8 114

Vinyl 4 0 0 0 4

Not Present 1 0 0 0 1

Table 33 Window Pane Type across Residential Structures

Window Pane Totals

Damage (Attached 

Combustible) Destroyed Damage No Damage

Not Determined 17 0 15 0 2

Single 60 1 12 1 46

Double 103 3 6 8 86

Triple 1 0 1 0

Other 1 0 1 0

Not Present 1 0 0 0 1
120

Appendix C Unconfirmed Defensive Actions
121

The data in this appendix (Table 34) represent information that was either not 

independently verifiable (labeled here as anecdotal) or information that was generic in 

location and could not be linked to a specific parcel and attribute. 

Table 34 Anecdotal Defensive Actions 

Defensive Action Comment Editor Comments

Engine 1 and Engine 2 came to assist 338 Cactus house on fire.

Anecdotal and could not confirm 

location of address.

Left 338 Cactus and went to defend another unknown house. Anecdotal

Came back to unknown location in Timber Creek to do mop-up. Unknown location

Truck protecting structure at Audach Ranch. Anecdotal

Brush 2 RCFD defending structure on Rocky Point Road.

Anecdotal and no fire occurred in 

area.

Attack 3, tanker 1, unit 3, brush 3 all came to Rocky Point road from 

Canyon Country Club fire; all worked until almost sundown. Anecdotal and unknown location.

Attack 2 and Brush 3 left to monitor and mop-up. Anecdotal

Happy Tanker truck and RCFD Tanker showed up to Rocky Point 

road for water. Anecdotal

204 Rocky Point; homeowner defending too. Anecdotal

Attack 2 went to east side of 204 Rocky Point Road to Defend Anecdotal

Defensive Action Comment Editor Comments

A little more water on RR ties at 411 Roberts by Timber Creek FD. Unknown location

Ravine on polar, 20-30 civilians fighting fire with shovels. Anecdotal

215 Quail Ridge - defended - Brooks home - sprinklers on. Brush 

truck in backyard. Family worked fence line.

Anecdotal and could not confirm 

location of address.

209 Quail Ridge - homeowner stayed and defended. Anecdotal

Ordered to protect two unknown homes in Timber Creek Unknown location

Passed hill drive and saw 2 small brush rigs from PANTEX. Anecdotal

Stayed on south side of creek all night putting out hot spots.

Anecdotal and no fire occurred in 

area.

Engine 1 and Engine 2 came to assist 338 Cactus house on fire. Anecdotal and unknown location.

Left 338 Cactus and went to defend another unknown house. Anecdotal

Came back to unknown location in Timber Creek to do mop-up. Anecdotal

Truck protecting structure at Audach Ranch. Anecdotal

Brush 2 RCFD defending structure on Rocky Point Road. Anecdotal

Attack 3, tanker 1, unit 3, brush 3 all came to Rocky Point road from 

Canyon Country Club fire; all worked until almost sundown. Unknown location

Attack 2 and Brush 3 left to monitor and mop-up. Anecdotal

Happy Tanker truck and RCFD Tanker showed up to Rocky Point 

road for water. Unknown location

204 Rocky Point; homeowner defending too. Unknown Palisades location

Attack 2 went to east side of 204 Rocky Point Road to Defend Unknown location

A little more water on RR ties at 411 Roberts by Timber Creek FD. Anecdotal

Ravine on polar, 20-30 civilians fighting fire with shovels. 

Anecdotal and unknown specific 

location.

215 Quail Ridge - defended - Brooks home - sprinklers on. Brush 

truck in backyard. Brooks family worked fence line. Anecdotal

209 Quail Ridge - homeowner stayed and defended. Anecdotal

Ordered to protect two unknown homes in Timber Creek Anecdotal

Passed hill drive and saw 2 small brush rigs from PANTEX. Anecdotal

Stayed on south side of creek all night putting out hot spots. Unknown location
122

Appendix D Suggested Improvements to the NIST WUI 

Assessment Defensive Action Methodology
123

Table 35 Issues and possible corrections with defensive action data collection methodology.

Defensive Action Issue Possible Correction

Many first responders had deleted images 

taken during the event by the time the 

discussion occurred.

At the onset of first responder discussions with each 

respective department, request that all images of the 

incident be provided to researchers. Obtain images at the 

discussion and have equipment to do this.

It was often difficult to determine which 

resource (e.g. Type I Engine) went with 

which first responder.

At the onset of first responder discussions with each 

respective department, request that a station roster 

associating individuals with resources be provided. 

Additionally, record the name, name of each staff, and 

characteristics of the resource used by the responder. 

Finally, when first responders change resources ensure this 

is recorded in the notes, if portrayed. Nonetheless, this 

situation appears to be common and would be difficult to 

quantify.

Several first responders referenced images 

that were not archived by data recorders.

Store and archive data using the NIST standard directory 

structure so that it can be retrieved by others using the data. 

Ensure data collectors have appropriate hardware to transfer 

photos from different devices.

Data recorders observed that more 

experienced fire fighters were more 

reliable in their recall of events compared 

to less experienced members.

At the onset of first responder discussions record the years 

of experience of staff members and have discussions with 

more senior staff members first.

Data sheets were not scanned until months 

or sometimes years after the discussion. 

Some notes were transcribed each night by 

typing, but these did not contain all the 

information present in the original notes 

and had transcription errors.

Ensure at a minimum that each night data sheets are

scanned or photographed, and archived appropriately. 

Ensure that data recorders have hand writing that is legible.

For many defensive action notes it could 

not be determined if the statement 

represented a timeline observation, a 

defensive action conducted by a third 

party, or a defensive action conducted by 

the respective first responder.

Develop a nomenclature to clearly identify the type of 

statement.

There was difficulty for some defensive 

action statements in determining if the 

defensive action represented a structure 

protection action or a containment action.

Develop a nomenclature to clearly identify the type of 

defensive actions.

Calibrate times for obtained images. At the time of collection of image, examine the imaging 

device and determine the time offset if any. Make sure to 

account for time changes.

Make an estimate in the field about 

accuracy of time estimates

Unless there is some other information to link time to first 

responder estimates, it is unlikely time estimates will be 

correct. Make sure the method to determine time is clearly 

documented
124

Appendix E Aspect Transformations
125

Slope and aspect might help to portray certain factors effecting fire behavior. The aspect 

calculations described here were necessary in order to derive the aspect for the different 

parcel within and around the fire perimeter. In order to average aspects within specified 

polygons, the aspect must be transformed to account for the measurement unit being in 

degrees. The aspect transformation performed required the following procedures:

1. Converting all flat aspect areas to no data values not included in subsequent 

procedures.

2. Converting the aspect grid in degrees to radians.

3. Calculating the sine and cosine of the aspect radians data set.

4. Summing the values of each sine and cosine aspect data set for each input 

polygon area.

5. Calculating the average aspect for each input polygon area using the equation 

below.

where FMOD is equivalent to the C function to return the floating point remainder of x divided by y

 Atan2 returns atan(x/y).
126

Appendix F Tabulation of Incident Data and Discussion
127

There were a total of 183 residential structures assessed in this study. Of these 183 

residential structures, 124 where within the mapped fire perimeter and an additional 59 

residential structures were outside the fire perimeter but had fire occurring within or close 

to the respective property boundary (i.e., parcel). This section presents building and 

topographic characteristics for these 183 structures.

Figure F1 displays damage status by building value15, 16. Figure F2 shows a bar graph 

displaying damage status by the year built. Table F1 lists damage status of residential 

structures by structure type. 

Figure 72 Residential structures by appraised building values and by damage status.

A more specific assessment of building materials is provided in 36 through 38. These 

tables show damage status by roof type, exterior siding, foundation type and the presence 

of fireplaces (as assessed by chimney presence). Foundation type is presented as 

assessed in the field and as assessed by the Potter-Randall County Tax District in Tables 

39 and 41, respectively. 

 

15 Mobile homes, abandoned buildings, and miscellaneous buildings did not have a building value. These 

homes were placed in the $0 - $50,000 category.

16 Potter and Randall County Tax Office, http://www.prad.org/
128

Figure 73 Residential structures by effective year built and by damage status.

Table 36 Damage status of residential structures by structure type.

No Damage Damaged17/ Destroyed Total

1 & 1/2 Story Log Home 0 (0 %) 1 (100 %) 1

1 & 1/2 Story Residential 20 (80 %) 5 (20 %) 25

One Story Residential 94 (76 %) 29 (24 %) 123

Split Level Residential 0 (0 %) 3 (100 %) 3

Two Story Log Home 1 (100 %) 0 (0 %) 1

Two Story Residential 13 (72 %) 5 (28 %) 18

Mobile Home 6 (55 %) 5 (45 %) 11

Abandoned Building 1 (100 %) 0 (0 %) 1

Total 135 (74 %) 48 (26 %) 183

Table 37 Damage status of residential structures by exterior type.

No Damage Damaged/ Destroyed Total

Concrete Block 7 (88 %) 1 (13 %) 8

Log 1 (100 %) 0 (0 %) 1

Masonry Veneer 89 (89 %) 11 (11 %) 100

Siding/Shingle/Metal 16 (41 %) 23 (59 %) 39

Stone Veneer 2 (100 %) 0 (0 %) 2

Stucco 11 (61 %) 7 (39 %) 18

Not Determined (Mobile Home) 9 (64 %) 5 (36 %) 14

Not Determined (Abandoned 

Building) 1 (100 %) 0 (0 %) 1

Total 135 (74 %) 48 (26 %) 183

 

17 Damaged includes homes with damaged or destroyed attached combustibles. The damage category does 

not include detached combustible objects.
129

Table 38 Damage status of residential structures by roof type.

No Damage Damaged/ Destroyed Total

Asphalt Shingles 92 (76 %) 29 (24 %) 121

Metal 20 (59 %) 14 (41 %) 34

Spanish Tile 3 (100 %) 0 (0 %) 3

Tar 6 (86 %) 1 (14 %) 7

Wood 9 (75 %) 3 (25 %) 12

Other 4 (100 %) 0 (0 %) 4

Not Determined 1 (50 %) 1 (50 %) 2

Concrete 

(Abandoned 

Building)

1 (100 %) 0 (0 %)

Total 135 (74 %) 48 (26 %) 183

Table 39 Damage status of residential structures by foundation type (NIST/TFS).

No Damage Damaged/ Destroyed Total

Slab 119 (82 %) 27 (18 %) 146

Raised Open 3 (38 %) 5 (63 %) 8

Raised Closed 7 (33 %) 14 (67 %) 21

Not Applicable 2 (100 %) 0 (0 %) 2

Not Determined 4 (67 %) 2 (33 %) 6

Total 135 (74 %) 48 (26 %) 183

Table 40 Damage status of residential structures by foundation type (Potter-Randall County).

No Damage Damaged/ Destroyed Total

Slab 109 (79 %) 29 (21 %) 138

Wood Subfloor 17 (55 %) 14 (45 %) 31

Not Determined 9 (64 %) 5 (36 %) 14

Total 135 (74 %) 48 (26 %) 183

Table 41 Damage status of residential structures by chimney presence.

No Damage Damaged/ Destroyed Total

Chimney(s) Present 102 (84 %) 20 (16 %) 122

No Chimney Present 10 (31 %) 22 (69 %) 32

Not Determined 23 (79 %) 6 (21 %) 29

Total 135 (74 %) 48 (26 %) 183

Average aspect18 in concentric buffers of 9.1 m (30 ft), 30.5 m (100 ft), 61.0 m (200 ft), 

91.4 m (300 ft) around each building footprint are shown in Tables 42 through 45. 

Average percent slope for the same buffer distances are shown in Tables 46 through 49. 

These buffer distances were selected as they are frequently used in existing hazard 

mitigation guidance such as NFPA 1144: Standard for Reducing Structure Ignition 

Hazards from Wildland Fire10

 

18 Average aspect over the entire buffer area.
130

Table 42 Damage status of residential structures by mean aspect (5m ((16.4 ft)) radar derived) within 

9.1 m (30 ft) around the structure.

No Damage Damaged/ Destroyed Total

North 25 (71 %) 10 (29 %) 35

Northeast 27 (84 %) 5 (16 %) 32

East 14 (78 %) 4 (22 %) 18

Southeast 17 (68 %) 8 (32 %) 25

South 28 (74 %) 10 (26 %) 38

Southwest 13 (93 %) 1 (7 %) 14

West 4 (50 %) 4 (50 %) 8

Northwest 7 (54 %) 6 (46 %) 13

Total 135 (74 %) 48 (26 %) 183

Table 43 Damage status of residential structures by mean aspect (5m ((16.4 ft)) radar derived) within 

30.5 m (100 ft) around the structure.

No Damage Damaged/ Destroyed Total

North 24 (73 %) 9 (27 %) 33

Northeast 27 (84 %) 5 (16 %) 32

East 20 (80 %) 5 (20 %) 25

Southeast 17 (65 %) 9 (35 %) 26

South 25 (76 %) 8 (24 %) 33

Southwest 11 (100 %) 0 (0 %) 11

West 5 (56 %) 4 (44 %) 9

Northwest 6 (43 %) 8 (57 %) 14

Total 135 (74 %) 48 (26 %) 183

Table 44 Damage status of residential structures by mean aspect (5m ((16.4 ft)) radar derived) within 

61.0 m (200 ft) around the structure.

No Damage Damaged/ Destroyed Total

North 33 (72 %) 13 (28 %) 46

Northeast 23 (85 %) 4 (15 %) 27

East 19 (66 %) 10 (34 %) 29

Southeast 15 (68 %) 7 (32 %) 22

South 30 (88 %) 4 (12 %) 34

Southwest 5 (71 %) 2 (29 %) 7

West 5 (83 %) 1 (17 %) 6

Northwest 5 (42 %) 7 (58 %) 12

Total 135 (74 %) 48 (26 %) 183
131

Table 45 Damage status of residential structures by mean aspect (5m ((16.4 ft)) radar derived) 

within 91.4 m (300 ft) around the structure.

No Damage Damaged/ Destroyed Total

North 36 (62 %) 22 (38 %) 58

Northeast 20 (83 %) 4 (17 %) 24

East 15(75 %) 5 (25 %) 20

Southeast 17 (81 %) 4 (19 %) 21

South 30 (88 %) 4 (12 %) 34

Southwest 2 (67 %) 1 (33 %) 3

West 4 (67 %) 2 (33 %) 6

Northwest 11 (65 %) 6 (35 %) 17

Total 135 (74 %) 48 (26 %) 183

Table 46 Damage status of residential structures by mean slope (5m ((16.4 ft)) radar derived) within 

9.1 m (30 ft) around the structure.

No Damage Damaged/ Destroyed Total

0 % - 2.5 % 40 (78 %) 11 (22 %) 51

2.5 % - 5 % 76 (70 %) 33 (30 %) 109

5 % - 7.5 % 14 (78 %) 4 (22 %) 18

7.5 % -10 % 4 (100 %) 0 (0 %) 4

10 % - 15 % 1 (100 %) 0 (0 %) 1

Total 135 (74 %) 48 (26 %) 183

Table 47 Damage status of residential structures by mean slope (5m ((16.4 ft)) radar derived) within 

30.5 m (100 ft) around the structure.

No Damage Damaged/ Destroyed Total

0 % - 2.5 % 57 (77 %) 17 (23 %) 74

2.5 % - 5 % 59 (68 %) 28 (32 %) 87

5 % - 7.5 % 14 (82 %) 3 (18 %) 17

7.5 % -10 % 3 (100 %) 0 (0 %) 3

10 % - 15 % 2 (100 %) 0 (0 %) 2

Total 135 (74 %) 48 (26 %) 183

Table 48 Damage status of residential structures by mean slope (5m ((16.4 ft)) radar derived) within 

61.0 m (200 ft) around the structure.

No Damage Damaged/ Destroyed Total

0 % - 2.5 % 49 (79 %) 13 (21 %) 62

2.5 % - 5 % 62 (65 %) 33 (35 %) 95

5 % - 7.5 % 19 (90 %) 2 (10 %) 21

7.5 % -10 % 5 (100 %) 0 (0 %) 5

10 % - 15 % 0 (0 %) 0 (0 %) 0

Total 135 (74 %) 48 (26 %) 183
132

Table 49 Damage status of residential structures by mean slope (5m ((16.4 ft)) radar derived) within 

91.4 m (300 ft) around the structure.

No Damage Damaged/ Destroyed Total

0 % - 2.5 % 47 (84 %) 9 (16 %) 56

2.5 % - 5 % 62 (65 %) 33 (35 %) 95

5 % - 7.5 % 23 (79 %) 6 (21 %) 29

7.5 % -10 % 3 (100 %) 0 (0 %) 3

10 % - 15 % 0 (0 %) 0 (0 %) 0

Total 135 (74 %) 48 (26 %) 183

Data Discussion

Understanding exposure, together with pre-fire information and defensive actions, are all 

essential in reconstructing the environment that affected buildings and detached 

combustibles in the WUI. 

Exposure quantification, however, in the post fire environment is difficult without in-situ 

instrumentation during the fire19. There is, however, a significant amount of exposure 

qualification that can be accomplished by collecting field data, discussions with first 

responders, and video and still imagery. This exposure information can then be used to 

understand and interpret ignition response, defensive actions and overall fire behavior. 

Additional exposure characterization information can be found in Section 14.7

For the entire incident, the data in this Appendix represents individual attributes for 

which data was available for both destroyed and non-destroyed structures. The 

information presented in this Appendix does not factor in exposure and defensive actions 

as was recommended in Section 1. This is the result of limited exposure information and 

incomplete defensive action data. While the following analysis has limitation in terms of 

both exposure and defensive actions, there is however value, in looking at all the exposed 

population, not only the structures that were damaged or destroyed. 

Field data collectors were instructed to assess properties where there was fire behavior 

within 30 m (100 ft) of the primary structure. Due to fire behavior information decaying 

with time, field data collectors did not always assess continuous properties and 

topographic conditions obscuring fire damaged or destroyed features. Consequently, the 

second field visit included additional properties on the edge of the fire, which might have 

been within 30 m (100 ft) of the fire, to ensure all possibly appropriate properties were 

assessed. Additionally, exposure conditions were observed to have varied greatly and 

one home that had fire behavior 15 m (50 ft) up wind from fire might have less exposure 

compared to another home 30 m (100 ft) downwind of fire behavior. Conversely, a home 

91 m (300 ft) from the fire might have more intense exposure conditions compared to a 

home 15 m (50 ft) away depending on wind, fuel and topographic conditions. 

The above two factors, coupled with a low sample population, result in it being 

inappropriate to use the data as presented below to assess structure response. This is 

clearly illustrated in Table 38 portraying structure response by roof type. A statistical 

analysis using Fisher’s Exact test of the data in Table F3 determined that there is a 

 

19 WUI mitigation effectiveness can reliably be assessed by utilizing in-situ instrumentation during 

wildfires or from control large scale experiments (prescribed burns).
133

somewhat significant difference (p-value of 0.055) between the different types of roofing 

(metal versus asphalt or wood) when looking at the damaged/destroyed versus the notdamaged structures. Table 38 data show that metal roofs have a higher percentage of 

destroyed homes compared to other categories, with only one home not being 

determined. This, however, is accounted for by the fact that eight of these homes were 

mobile homes, where metal roofs are a common roof type. Other homes with metal roofs 

were in areas where fire spread might have been structure to structure fire spread. Some 

homes with metal roof had damage to other structural elements (e.g. eaves and broken 

windows). 

The data presented above is presented as a first exploratory look at the data from which to 

subdivide into more appropriate populations for appropriate analysis of exposure and 

vulnerabilities using the data presented in this report, coupled with electronic spatial and 

tabular databases produced as part of this effort. The greatest hindrance from further 

assessment of the data would be lack of a good timeline for areas burned in the Palisades 

Communities and an inevitable low sample size.
134

Appendix G Recommendations for Improvements to WUI 2 Data 

Collection System
135

The WUI 2 Data Collection System implemented at the Tanglewood Fire collected a 

large amount of information that could not be used for analysis because consistent 

information did not exist for all homes (i.e., unless the building material was present in 

the tax assessor data) or because there was confusion in interpretation of attributes. 

Consequently, the overall data collection should be streamlined as follows:

1. Collection of structural information should be very limited, focusing on location 

of features, recording of damage condition and extensive photographic 

information. 

2. Based on pre-fire building information available, it is recommended that accuracy 

assessments be conducted on sub-populations of homes not destroyed to confirm 

the validity of the data.

3. Topographic information should be obtained from high-resolution surveying or 

remote data sources. The required resolution is unknown and might be incident 

dependent. Nonetheless, some simple studies using information from the study 

of the Trails at Rancho Bernardo9, 12 community might provide some insight into 

the impact of topographic resolution on the interpretation of fire behavior.

4. Post-fire WUI assessments require timely post-fire aerial imagery. Without high 

resolution post-fire imagery (e.g. less than 0.3 m ((1 ft)) spatial resolution; 

further quantification is required) post-fire WUI assessments should not be 

conducted, as critical information on fire behavior and fuel consumption will not 

be available to provide context for the event reconstruction.

5. A plot based system should be developed for collection of post-fire vegetation 

information in the wildlands adjacent to the WUI. The post-fire imagery, along 

with pre-fire imagery, can be used to group the populations into subsets for 

appropriate sampling.

6. Collection of post-fire vegetation information in residential areas should be 

greatly simplified with a large emphasis on imaging of features. The onscreen 

digitizing of burned vegetation using pre-fire imagery did not result in a directly 

usable dataset in part due to varying skills in digitization as seen in Figure 74. In 

addition to varying degrees of digitizing expertise amongst data collectors, even 

an experienced digitizer often had errors such as flipping the orientation of 

burned vegetation, as shown in the figure below. The use of post-fire imagery as 

a base layer will aid in producing a more directly usable data set. However, 

being that data collectors are unlikely to be Geospatial professionals, it should be 

expected that the field data set will still require extensive post-processing. 

7. Pre-fire information must also exist regarding vegetation. This requires, again, 

remote sensing data of adequate spatial, temporal and spectral resolution (i.e., 

less than 0.3 m (1 ft) horizontal resolution, acquired less than two years before 

incident, and having four bands of data including information in the nearinfrared).

8. Even the above information might not be enough for adequate characterization of 

the fire disturbance continuum without adequate ground images, particularly 

residential vegetation.

9. WUI communities should be encouraged to use an appropriate plot based 

sampling technique for recording information about adjacent wildlands in prefire conditions, the same way parcels are documented within the community.
136

Figure 74 Erroneous field collected burn vegetation boundary

10. The focus of post-fire assessments should be on timely acquisition of burned 

vegetation data. The WUI 2 deployment at the Tanglewood Fire focused on 

documenting building material on destroyed homes first, so as not to lose

information during building cleanup. However, very little information was able 

to be discerned about destroyed buildings. Additionally, this focus resulted in 

loss of information regarding burned vegetation on properties with nondestroyed structures but containing burned vegetation. The focus of WUI 2 postfire assessments, initially, should be on collection of burned vegetation 

information across the study area along with fire direction indicators.

11. Local authorities having jurisdiction (AHJ) should be the entities that conduct 

preliminary damage assessments because of their familiarity with the local 

environment. A new WUI 1 form should be developed that focuses on damage 

assessment only. Other simple assessments of building characteristics and 

vegetation require more in-depth study, as described above. This simple damage 

assessment can be incorporated into the WUI 2 assessments for efficiency.

12. All features collected should have extensive image documentation because, 

without documented images, quality assurance and quality control processes will 

be significantly hampered. However, images should be taken with efficiency in 

mind. The respective site should be photographed with the minimum number of 

images possible to capture the entire scene. Technologies such as PhotosythTM

Background: City of 

Amarillo, used by 

permission, overlays NIST
137

allow for simple creation of a 3D panoramic image. If logistics allow, these can 

simply be posted to Bing Maps or other such sites to facilitate detailed ground 

imaging of the entire scene.

13. Standard images should always be associated with the specific feature.

14. Post-fire assessments require adequate determination of the fire timeline. First 

responder discussions alone do not suffice to determine burn times of features. 

As described above, images and GPS locations are required to adequately 

recreate the fire timeline. 
138

Appendix H Example of Pre-Fire WUI Mitigation Advice Form 

Implemented in Areas Affected by the Tanglewood Fire
139

The field form in this Appendix is from a pre-fire assessment of the Tanglewood Fire 

area, which occurred on some unknown date prior to the Tanglewood Fire. The data was 

incomplete, not in electronic format, nor complete for the entire community, and could 

not be used in this assessment. 
140
141
142
143

17.0 References

 

1

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18 A Technical Research Burn Conducted to Develop Field Methodologies for Wildfire 

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22 http://www.fs.fed.us/pnw/fera/wfds/index.shtml

23 http://code.google.com/p/fds-smv/