The views and conclusions contained in this document are those of the authors and should not be 

interpreted as representing the opinions or policies of the U.S. Government. Mention of trade names or 

commercial products does not constitute their endorsement by the U.S. Government.

FINAL REPORT

Title: An Assessment of Research Needs 

Related to Wildland Firefighter Safety

JFSP PROJECT ID: 18-S-01-1

May 2019

Matt Jolly

US Forest Service, RMRS, Fire Sciences Laboratory

Bret Butler

US Forest Service, RMRS, Fire Sciences Laboratory

Wesley Page

US Forest Service, RMRS, Fire Sciences Laboratory

Patrick Freeborn

US Forest Service, RMRS, Fire Sciences Laboratory
i

Table of Contents

List of Tables .................................................................................................................................. ii

List of Figures................................................................................................................................. ii

List of Abbreviations/Acronyms..................................................................................................... ii

Keywords........................................................................................................................................ ii

Abstract........................................................................................................................................... 1

Objectives ....................................................................................................................................... 2

Background..................................................................................................................................... 2

Literature review.......................................................................................................................................3

Entrapment definition ...............................................................................................................................3

Human factors...........................................................................................................................................3

Firefighter Entrapment Database .................................................................................................... 4

Data sources..............................................................................................................................................4

Database creation, storage and access.......................................................................................................4

Key Findings................................................................................................................................... 6

Finding 1: Previous investigations of firefighter entrapment incidents have similar summaries and 

recommendations......................................................................................................................................6

Finding 2: The entrapment investigation process and existing data reporting/storage systems are flawed

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

Finding 3: There is likely a substantial under-reporting of entrapment incidents.....................................9

Finding 4: The number of entrapment-related fatalities are decreasing but the number of entrapment 

incidents are not ........................................................................................................................................9

Finding 5: Factual information from previous entrapments can be used to predict/project future 

entrapment hazard and risk ..................................................................................................................... 13

Research Needs............................................................................................................................. 16

Inadequate knowledge............................................................................................................................. 16

Inadequate tools ...................................................................................................................................... 17

Improved data collection and storage ..................................................................................................... 18

Literature Cited ............................................................................................................................. 21

Appendix A: Contact Information ............................................................................................... A1

Appendix B: List of Products ...................................................................................................... A2

Online firefighter entrapment database (1979-2018)............................................................................. A2

Articles in peer-reviewed journals......................................................................................................... A2

Other published materials ...................................................................................................................... A2
ii

List of Tables

Table 1. Common US wildland firefighter safety protocols, guidelines and their origins.

Table 2. Some of current tools used by wildland firefighters and their limitations related to 4 of 

the standard firefighting orders.

Table 3. Recommended data collection and reporting standards for the relevant fire environment 

variables associated with firefighter entrapments that involve a burnover.

List of Figures

Figure 1. US wildland firefighter fatalities by cause, 1990 to 2016. Originally published as 

Figure 1 in NWCG (2017).

Figure 2. Screen shot of the online version of the Fire Sciences Lab Merged Entrapment 

Database, see https://www.wfas.net/entrap/.

Figure 3. US wildland firefighter entrapments where there was a burnover, 1979-2017.

Figure 4. Visual representation of word and phrase frequency in the form of a word cloud based 

on the wildland firefighter guidelines and safety protocols listed in Table 1.

Figure 5. Entrapment-related fatality data for wildland firefighters in the Continental US, 1926 

to 2017.

Figure 6. Entrapment-related wildland firefighter fatality rates in the Continental US, 1992 to 

2015.

Figure 7. Trends in all firefighter entrapments where there was a burnover in the Continental US 

between 1987 and 2017.

Figure 8. Schematic representation of an example process to assess and predict firefighter 

entrapment potential across space and through time.

Figure 9. Two methods for predicting the likelihood of an entrapment on December 14, 2017 

near the location of the Thomas Fire fatality within the boundaries of the Boulder Creek-Sespe 

Creek watershed in Southern California.

List of Abbreviations/Acronyms

FiSL MED – Fire Sciences Lab Merged Entrapment Database 

GACC – Geographic Area Coordination Center

JFSP – Joint Fire Science Program

NWCG – National Wildfire Coordinating Group

US – United States

Keywords

Burnover, entrapment investigation, entrapment data, fire behavior, fire environment, firefighter 

fatalities
1

Abstract

Wildland firefighters in the United States (US) are exposed to a variety of hazards while 

performing their jobs in America’s wildlands. Although the threats posed by vehicle accidents, 

aircraft mishaps and heart attacks claim the most lives (Figure 1), situations where firefighters 

are caught in a life-threatening, fire behavior-related event (i.e. an entrapment) constitute a 

considerable danger because each instance can affect many individuals. In an attempt to identify 

the scope of our understanding of the causes of firefighter entrapments a review of the pertinent 

literature and a compilation and synthesis of existing data was undertaken. The literature review 

and the creation of a firefighter entrapment database (https://www.wfas.net/entrap/) led to the

identification of five key findings: (1) previous investigations of firefighter entrapment incidents 

have similar summaries and recommendations, (2) the entrapment investigation process and 

existing data reporting/storage systems are flawed, (3) there is likely a substantial underreporting of entrapment incidents, (4) the annual number of entrapment-related fatalities are 

decreasing but the number of entrapment incidents are not and (5) information from previous 

entrapments can be used to predict/project future entrapment hazard and risk. A summary of 

research needs is also presented.

Figure 1. US wildland firefighter fatalities by cause, 1990 to 2016. Originally published as Figure 1 in 

NWCG (2017).
2

Objectives

The Joint Fire Science Program’s (JFSP) Governing Board recognizes the need for further 

research on topics related to firefighter safety and has requested an assessment of the current 

state-of-knowledge and potential role of the JFSP in sponsoring research into entrapment 

avoidance, escape routes and safety zones. Given the expertise and background of the project 

team members, an analysis of the various environmental factors that affect firefighter safety in 

relation to firefighter entrapments was undertaken. Our objectives were to: (1) establish a 

focused research team consisting of 2 lead scientists and 2 post-doctoral researchers to facilitate 

project execution, (2) conduct a comprehensive subject matter review, (3) compile and 

synthesize the available information to infer trends and evaluate potential research opportunities, 

(4) assess knowledge gaps and summarize expressed needs of fire managers and (5) produce 

recommendations on possible avenues of future research. The primary product of the assessment 

is a Review article (Page et al. In review), thus readers should refer to that article for specific 

details regarding the project findings. 

Background

Since the introduction and adoption of a centralized suppression-oriented wildland firefighting 

paradigm in the US, wildland firefighters have been employed to protect and manage various 

natural and human resources. Both wildland fire scientists and firefighters have long noted the 

numerous challenges involved with such an undertaking due to the complexities of wildland fire 

as a physical process (Finney et al. 2015) and the social and behavioral aspects of individuals 

and organizations (Putnam 1996). Unfortunately, the combination of well-meaning and actionoriented attitudes with dynamic and volatile fire environments has resulted in hundreds of 

entrapment-related firefighter deaths (Mangan 2007; NWCG 2017). Despite these fatalities, 

some of which have garnered substantial public attention (e.g. Yarnell Hill), investment in 

fundamental research that directly focuses on how firefighters assess and reassess fire behavior, 

escape routes and safety zones to avoid entrapments has been limited. 

In an effort to better understand the current state-of-knowledge associated with 

firefighter entrapments in the US a review and synthesis was completed. The review covered the 

extant body of scientific, technical, investigative and instructional subject matter, and included a

survey of several prominent entrapment reporting systems. In combination, the literature review 

and the most comprehensive firefighter entrapment database compiled to date were used to 

identify several key findings.
3

Literature review

During the review we consulted a variety of published work that dealt directly or indirectly with 

firefighter entrapments in the US. Specifically, we reviewed:

 > 100 firefighter entrapment investigation reports,

 > 50 peer-reviewed papers, 

 ~ 40 agency-produced technical reports,

 ~ 30 articles from the so-called grey literature (i.e. conference proceedings, non-refereed

articles, etc.), and

 ~ 10 personal opinion articles.

References to the pertinent literature can be found in the bibliographies published at the end of 

this report as well as in Page et al. (In Review). 

Entrapment definition

During the literature review we recognized that there currently exists some confusion in the 

wildland fire community about the differences/similarities between the terms ‘entrapment’ and 

‘burnover’. Therefore, before continuing we sought to clarify the terminology in order better 

facilitate project execution by producing an encyclopedic entry (see Page and Freeborn In press). 

Page and Freeborn (In press) state that an entrapment includes situations where a fire behaviorrelated event poses an immediate threat to peoples’ lives because (1) a fire moves through and 

overtakes individuals (i.e. a burnover) or (2) the individuals escape by will or luck (i.e. a nearmiss or close call). Thus, a burnover is a specific type of entrapment where the threat to peoples’ 

lives becomes actualized. Due to the likely significant under-reporting bias associated with nearmisses (see Finding 3), our review focuses on entrapments where there was a burnover. 

Human factors

Data and knowledge of the environmental factors that affect fire behavior can only move our 

understanding of how and why entrapments occur so far. A significant portion of our 

understanding of entrapment potential lies in the human factors. The human dimensions of 

wildland firefighting represent a broad range of topics and disciplines, including psychology, 

sociology, leadership and fire safety (Putnam 1995). Larson et al. (2007) present a diverse 

assortment of approximately 270 sources of information related to human factors that are

relevant to wildland firefighting organizations and culture. While the effect of human decisionmaking on wildland firefighter entrapments is clear (see Putnam 1995), a detailed accounting of 

these effects is beyond the scope of the current project. 

The current federal wildland fire policy stipulates that land management plans and fire 

management plans incorporate the best available science supplied by an active, interagency fire 

research program (Fire Executive Council 2009). Whilst fire management plans are written to 

reflect firefighter and public safety as the first priority, it is less apparent whether incident 

commanders and firefighters consult the best available science and information delivery systems 
4

when developing strategies and operational tactics. Human factors play a role in determining 

how firefighters incorporate and implement new research findings into operational decisionmaking. For example, Alexander et al. (2016) noted a gap in the understanding of how 

firefighters utilize various fire behavior prediction tools to assess escape routes and fire travel 

times. Although it is currently unclear if and how wildland firefighters incorporate new research 

findings into their standard operating procedures, an analysis of fire research outcomes by fire 

managers suggested that a lack of manager awareness was a barrier to successful application of 

science (Hunter 2016). Work from other disciplines also indicates that perceived usefulness, 

ease of use and the need to acquire additional skills are common barriers to successful 

integration (Farzandipur et al. 2016). Additional research is needed to fully identify the factors 

associated with successful dissemination of new research into the field. 

Firefighter Entrapment Database

Objective 3 – Compile and synthesize available information

Data sources

Data from several US-based reporting and storage systems for entrapment-related wildland 

firefighter fatalities and injuries were compiled. The data sources comprise the five surveillance 

systems noted by Butler et al. (2017), which include databases maintained by the US Fire 

Administration, the National Fire Protection Association, the US Bureau of Labor Statistics, the 

National Institute for Occupational Safety and Health and the Risk Management Committee of 

the National Wildfire Coordinating Group (NWCG). Additional formal and informal storage 

systems reviewed included the Wildland Fire Lessons Learned Center Incident Review Database 

(Available at https://www.wildfirelessons.net/irdb [accessed 8 February 2019]) and the Always 

Remember! website (Available at https://wlfalwaysremember.org/ [accessed 8 February 2019]). 

Database creation, storage and access

All existing data that could be acquired along with supplemental verbal and written responses 

from fire managers about specific incidents were merged into a database of firefighter 

entrapments, referred to as the Fire Sciences Lab Merged Entrapment Database (FiSL MED). 

The database has been made available online (see https://www.wfas.net/entrap/) (Figure 2) and

includes information on the location, date and approximate time (GMT), number of personnel 

involved, the number of fatalities and location quality for entrapments with a burnover that have 

occurred within the Continental US since 1979 (Figure 3). Location quality is currently 

classified into 4 categories; Estimated – an estimated location based on the description provided 

in the entrapment investigation, Fire start location – the location of the origin of the fire with the 

entrapment, Good – actual entrapment location, and Unavailable – no known location 

information. The year 1979 marks the beginning of the availability of high quality gridded 

weather data (i.e. Abatzoglou 2013) and also coincides with the availability of other dynamic fire 

environment data such as fuel type information derived from Landsat imagery (e.g. Kourtz 
5

1977). As of March 2019 the database contains 342 known entrapment incidents, of which 193 

(56%) have accurate spatial locations, with the remaining entrapments currently limited to the 

reported location of the fire origin associated with the entrapment (32%), estimated based on 

written descriptions (8%) and those entrapments with no known location information (4%). 

Figure 2. Screen shot of the online version of the Fire Sciences Lab Merged Entrapment Database, see 

https://www.wfas.net/entrap/.

Figure 3. US wildland firefighter entrapments where there was a burnover, 1979-2017.
6

Key Findings

Objectives 2, 3 and 4 – Undertake comprehensive review, synthesize findings and assess 

knowledge gaps

Finding 1: Previous investigations of firefighter entrapment incidents have similar 

summaries and recommendations

With few exceptions, major systemic reviews have been initiated following either single fires or 

groups of fires that had entrapment-related fatalities (e.g. Moore et al. 1957; Bjornsen et al.

1967, Wilson 1977; NWCG 1980). Many of these reviews have formed the basis of training 

aids, guidelines and safety protocols (Table 1). Despite the fact that these training aides and 

guidelines summarize findings from dozens of fires where hundreds of firefighters were killed

over a period of more than 60 years they contain much of the same content (Figure 4). 

The similarities among the safety guidelines, protocols and entrapment investigation 

recommendations have been noted by others. Specifically, a task force established following a 

series of fatality fires in the late 1970s (NWCG 1980) recognized the repeating patterns in 

fatality investigation reports related to both the fire environment and the subsequent investigation 

recommendations. They noted that part of the problem was associated with “...incomplete 

implementation of previous studies’ recommendations.” More recently, others (e.g. Gabbert 

2019) have continued to recognize that the recommendations contained within investigation 

reports are rarely unique and are often duplicates of previous findings. 

Finding 2: The entrapment investigation process and existing data 

reporting/storage systems are flawed

Today, the typical document produced following entrapments on federally managed land is 

similar to a Facilitated Learning Analysis (USDA Forest Service 2016). These documents tend 

to have a long narrative format with little summary information. The lack of basic information 

(e.g. latitude and longitude, description of entrapment site) in these documents and the format in 

which they are presented (e.g. long paragraphs) makes it difficult to gather and objectively assess 

important factual information. 

While many of the US agency-specific investigation guides do reinforce the 

importance of documenting the natural features at an entrapment site (Mangan 1995), it seems 

that in reality many of the details either fail to be measured/described or included in the final 

report. Page and Butler (In press) note that after reviewing over 200 entrapment investigation 

reports only a minority (~75) contained suitable information on both the fire environment (fuels, 

weather and topography) in/around the entrapment site and the size of the refuge area (i.e. 

physical dimensions) to adequately assess the influence of these factors on entrapment 

survivability. The failure to permanently record this important information represents a huge 

loss to current and future wildland firefighters. 
7

Table 1. Common US wildland firefighter safety protocols, guidelines and their origins.

Guideline Brief description Source

Accident Check List for Forest Fire 

Fighters

A list of approximately 48 items under 11 categories 

submitted by the California Region of the US Forest 

Service to improve firefighter safety.

US Forest Service 

California Region 

(1954)

Standard Fire Orders

Ten standard orders to follow while engaged in 

wildland fire operations. Based on an analysis of 16 

fires between 1937 and 1956 where 79 firefighters 

perished.

McArdle (1957)

Watch Out Situations (Standards for 

Survival)

Eighteen environmental and operational situations that 

warrant caution when engaged in wildland fire-related 

activities. The original list of 13 situations were 

developed sometime between 1967 and 1975.

Origin unclear, see 

Ziegler (2008)

Downhill Checklist

Specific requirements that must be in place prior to 

building fireline downhill. Based on an analysis of 3 

fires where firefighters died while constructing 

downhill fireline.

Bjornsen et al. (1967)

Common Denominators of Fire

Behavior on Tragedy Fires

Five common characteristics among 67 fires that had 

fatalities between 1926 and 1976. Wilson (1977)

Common Denominators of Fire 

Behavior on Fatal and Near-fatal Fires

Four common characteristics among 67 fatal and 31 

near-fatal fires between 1926 and 1976. Wilson (1977)

Eight Firefighting Commandments

A list of 8 items to obey while engaged in fire 

suppression operations. Formulated based on the 

acronym WATCH OUT.

NWCG (1980)

Thirteen Prescribed Fire Situations 

that Shout Watch Out

A list of 13 items that warrant caution during 

prescribed fire operations. Maupin (1981)

LCES

A system for operational safety, which emphasizes 

Lookout(s), Communication(s), Escape Routes and 

Safety Zone(s).

Gleason (1991)

Look Up, Look Down, Look Around List of environmental indicators that may be indicative 

of the potential for extreme fire behavior. NWCG (1992, 2018)

Fire Environment Size-up Model (Risk 

Management Process)

A 4 step model developed from the results of a survey 

of experienced wildland firefighters that can be used as 

a decision support system.

Cook (1995)

21st Century Common Denominators 

for Wildland Firefighter Fatalities

A list of the four major causes of firefighter fatalities 

between 1990 and 2006. Mangan (2007)

Common Denominators on Tragedy 

Fires – Updated for a new Human Fire 

Environment

Eight human factors common to fires where there was a 

fatality. Developed with a focus on fatality fires that 

have occurred in the 21st century.

Holmstrom (2016)

Common Tactical Hazards Ten items related to firefighting tactics that may affect 

firefighter safety. NWCG (2018)
8

Figure 4. Visual representation of word and phrase frequency in the form of a word cloud based on the 

wildland firefighter guidelines and safety protocols listed in Table 1. Larger words occurred more 

frequently in the guidelines and those words with the same color occurred in similar proportions. 

The current reporting and storage systems for data related to wildland firefighter 

entrapments also have several issues. Either by law or practice many of the systems store data 

related to the same incident, which is both inefficient and potentially confusing. As noted by 

Butler et al. (2017), some systems are required to track firefighter fatalities due to various legal 

statutes, while others may not include fatalities associated with some specific tasks and duties. 

Having multiple reporting systems with different inclusion criteria makes it difficult to assess the 

quality and completeness of the various datasets. 

Two wildland fire-specific systems stand out as having the potential to fill the role as 

the primary repository for housing data related to entrapment injuries and fatalities, namely the 

NWCG Safety Grams and the Wildland Fire Lessons Learned Center Incident Review Database. 

In their current form each system has unique advantages and disadvantages that requires the use 

of both to gather and compile adequate temporal, spatial and physical information associated 

with each incident. For example, the NWCG Safety Grams do not provide specific details 

regarding the time, exact location or environmental conditions associated with the reported 

incidents. Conversely, the Incident Review Database does have links to reports that contain 

details associated with entrapment incidents, but older incidents tend to have little/no

documentation and as noted above, much of the documentation is of poor quality and does not 

provide adequate factual information about the entrapment. 
9

As of the writing of this report there is no one dataset that can be consulted which 

contains adequate information on the spatial location, time, and other specific information for 

wildland firefighter entrapments in the US. The FiSL MED represents an attempt to initiate such 

a database but a long-term plan to update and maintain the database is needed. 

Finding 3: There is likely a substantial under-reporting of entrapment incidents

Firefighter entrapments include situations where fire moves through or overtakes personnel (i.e. 

a burnover) and where personnel avoid being overtaken by fire due to will or luck. In our 

assessment we focused the data collection and synthesis efforts on entrapments where there was 

a burnover. This was due to the likely significant under-reporting bias related to entrapments 

considered to be near misses or close calls. Strohmeyer et al. (2018) note that a stigma among 

firefighters tends to result in a resistance to label events as entrapments in order to avoid the 

attention and scrutiny that may follow. Additionally, prior to the late 1980s the existing 

firefighter entrapment databases seem to have a priority for storing information related to fatal 

firefighter entrapment incidents, rather than non-fatal burnovers and near-misses. Thus, there is 

likely a significant under-reporting bias for firefighter burnovers and near-misses prior to the late 

1980s.

Although near-misses or close calls usually don’t result in significant injuries, they 

still represent situations that can provide valuable insights into the conditions that result in rapid 

changes in fire behavior and how those changes affect firefighter safety. Much of the basic fire 

environment information relevant to entrapments that result in a burnover is also relevant to 

near-misses, with the primary difference being the lack of a specific entrapment location. In 

order to utilize the data associated with these incidents it is recommended that firefighters and 

fire managers report and investigate these incidents the same way they do incidents that resulted 

in a burnover. Extra details regarding the escape routes utilized would provide additional useful 

information. 

Finding 4: The number of entrapment-related fatalities are decreasing but the 

number of entrapment incidents are not

To date the majority of reports summarizing firefighter entrapments in the US have only 

presented data related to the number of fatalities through time. All of these summaries have been 

at least partially based on the data compiled by the NWCG and stored by the National 

Interagency Fire Center. A compilation of this data is presented based upon the annual number 

of entrapment-related fatalities between 1926 and 2017 (Figure 5) and associated entrapment 

rates using the number of fires and area burned between 1992 and 2015 (Figure 6).

Similar to the findings provided in other published sources, there has been a 

downward trend in the annual number of entrapment-related fatalities since 1926 (Figure 5). 

Despite several peaks associated with high fatality events, the annual number of entrapmentrelated fatalities has been dropping by approximately 0.4 (6%) fatalities per decade, although the 

trend is only marginally significant (P-value = 0.157). 
10

Figure 5. Entrapment-related wildland firefighter fatalities in the Continental US, 1926 to 2017. The 

nonparametric Mann-Kendall test (Mann 1945; Kendall 1975) was used to identify the presence of 

significant monotonic trends. The value τ represents the Kendall rank correlation coefficient, i.e. the 

strength of the relationship, with the corresponding probability that the trend does not exist (P-value). 

Data were compiled from National Interagency Fire Center (2018).

When the annual number of entrapment-related fatalities are viewed in relation to the 

annual number of fires and area burned additional trends can be inferred. Unfortunately, due to 

the lack of high quality data on US fire activity for all fire sizes prior to 1992 (Short 2015) the 

current analysis is limited to years with the best data, 1992 to 2015 (Figure 6; Short 2017). The 

analysis indicated that the highest fatality rate by area burned occurred in 2013 (~0.6 per 100 000 

ac (40 469 ha) burned) due to the 19 fatalities on the Yarnell Hill Fire (YHFI Report 2013), with 

the lowest average rates found in the late 1990s and early 2000s. Since 1992 the average number 

of fatalities per 100 000 ac (40 469 ha) burned has decreased by approximately 0.01 (9%) per 

decade, which is marginally significant. However, the fatality rates based on the yearly number 

of fires shows little change with an average of about 0.5 fatalities per 10 000 fires or 1 fatality 

every 20 000 fires (Figure 6a). There has been a general decrease in the annual number of 

wildland fires in the US over the same time period, which accounts for the fatality rate remaining 

unchanged even though the total number of fatalities has been decreasing. 

Those entrapments that occurred between 1987 and 2017 (i.e. 285) represent the 

period that encompasses the most overlap between existing entrapment databases. The data 
11

during this time period reveal that the total number of entrapment incidents, i.e. those with and 

without fatalities, have not been significantly declining during this period (Figure 7). However, 

there does seem to be a declining trend in the average number of personnel entrapped per 

incident, decreasing at a rate of approximately 0.8 people per decade, although the relationship 

was not statistically significant (Figure 7b). Although the absence of statistically significant 

upward trends in fatalities and entrapments is encouraging, the results of the trend analysis 

should not dissuade further understanding of the circumstances that lead to these rare and highly 

consequential events. 

Figure 6. Entrapment-related wildland firefighter fatality rates in the Continental US from 1992 to 2015 

by (a) the number of fatalities per 10 000 fires and (b) the number of fatalities per 100 000 ac (40 469 ha) 

burned. The nonparametric Mann-Kendall test (Mann 1945; Kendall 1975) was used to identify the 

presence of significant monotonic trends. The value τ represents the Kendall rank correlation coefficient, 

i.e. the strength of the relationship, with the corresponding probability that the trend does not exist (Pvalue). Data were compiled based on number of fires and area burned from Short (2017) and fatalities per 

year provided by the National Interagency Fire Center (2018). 
12

Figure 7. Trends in all firefighter entrapments (i.e. with and without a fatality) where there was a 

burnover in the Continental US between 1987 and 2017 by; (a) Geographic Area Coordination Center 

(GACC) and (b) the total number of entrapment incidents and the average number of personnel per 

entrapment incident. Note that North Ops and South Ops in (a) represents Northern and Southern 

California, respectively. The nonparametric Mann-Kendall test (Mann 1945; Kendall 1975) was used to 

identify the presence of significant monotonic trends. The value τ represents the Kendall rank correlation 

coefficient, i.e. the strength of the relationship, with the corresponding probability that the trend does not 

exist (P-value). The boundaries of the GACCs are shown in Figure 3. 
13

Finding 5: Factual information from previous entrapments can be used to 

predict/project future entrapment hazard and risk

In addition to consulting the firefighter safety protocols and guidelines (Table 1), we suggest that 

firefighters could benefit from access to maps that identify the environmental conditions 

common to previous entrapments. Characterizing the environmental conditions at the location 

and time of an entrapment allows the development of relationships that can be used to predict 

entrapment potential across space and through time (Figure 8). For example, spatially-explicit 

data on both static (i.e. fuels and topography) and dynamic variables (i.e. fire weather) during 

previous entrapments could be used with statistical models to produce maps that depict the 

locations and times when entrapment potential is high. Figure 9 illustrates an example 

application using two methods of modelling entrapment potential for an area around a firefighter 

fatality that occurred during the Thomas Fire on December 14, 2017 in Southern California 

(California Department of Forestry & Fire Protection 2017). 

According to the first method based on several fuel and topographic characteristics 

described by Page and Butler (2018), the Thomas Fire entrapment occurred within one of the 

most dangerous watersheds (Boulder Creek-Sespe Creek) for firefighters in Southern California, 

with only 3% of other similar watersheds being ranked as more dangerous (Figure 9a). 

Likewise, according to the second method based on an analysis using rare-event logistic 

regression (Imai et al. 2008) with the compiled entrapment data and predictor variables of fire 

weather and slope steepness, much of the area in and around the entrapment location had high 

potential for an entrapment (Figure 9b). Similar methods and outputs may eventually be useful 

sources of information for wildland firefighters as they refine situational awareness before and 

during fire suppression operations.

In addition to near real time applications, models capable of mapping entrapment 

potential based on environmental conditions could be used to reconstruct or forecast long-term 

changes across the landscape or over time. For example, a daily gridded climatology and a 

dynamic fuels map could be overlaid with a digital elevation model (DEM) to quantify the 

expansion or contraction of entrapment potential both seasonally and over the course of several 

decades. Entrapment potential could then be used to quantify spatial and temporal trends in 

firefighter exposure, and area-wide summaries of entrapment potential could possibly be used as 

an alternative to the number of fires or burned area as a means of normalizing fatality and 

entrapment rates. Regardless of the application, it is important to reiterate that the goal of any 

such model would be to identify the environmental conditions most similar to those found at the 

locations and times of previous entrapments. At the cost of reducing the sample size, creating 

separate models using subsets of the full entrapment database could reveal regional and/or 

temporal variations in the environmental conditions surrounding the entrapments. Moreover, it 

must be recognized that combinations of environmental conditions that support rapid 

accelerations towards extreme fire behavior will not be identified as “dangerous” if an 

entrapment was never recorded under those conditions. Shifts in firefighting strategies and 
14

tactics into fire environments capable of supporting extreme fire behavior but where an 

entrapment was never recorded will challenge this empirical modelling approach. 

Figure 8. Schematic representation of an example process to assess and predict firefighter 

entrapment potential across space and through time. Important environmental data gathered at 

previous entrapment locations is coupled with statistical models to derive relationships that can 

be used to predict future entrapment potential.
15

Figure 9. Two methods for predicting the likelihood of an entrapment on December 14, 2017 near the 

location of the Thomas Fire fatality within the boundaries of the Boulder Creek-Sespe Creek watershed in 

Southern California. Predictions are based on; (a) the maximum entropy methods for several fuel and 

topographic factors as described by Page and Butler (2018) and (b) logistic regression using fire weather 

(Energy Release Component and Burning Index) and slope steepness from the merged fire occurrence and 

entrapment database.
16

Research Needs

Objective 5 – Recommendations

The subject of wildland firefighter safety is complex with aspects of the physical and biological 

sciences as well as psychology (individuals) and sociology (cultures). Achieving significant 

progress towards developing solutions that will improve firefighter safety requires a coordinated 

multi-year, multi-project approach. Implementing such a complex program of work necessitates

the identification of specific research objectives that are complimentary and build on each other 

through time. Given the current state of wildland fire science and management, defining those

objectives will be difficult as it is currently unclear what the desired end-state or outcomes are of 

the various stakeholders, i.e. firefighters, fire managers, land managers and the public. It is 

reasonable to suspect that all stakeholders would want to minimize the dangers posed to wildland 

firefighters and eliminate firefighter deaths and injuries, but it is not clear what tradeoffs are 

associated with the inevitable shift in risk to other values that would need to occur in order to

make that a reality. 

This project provided an initial scientific assessment of the problem of wildland 

firefighter safety through the lens of firefighter entrapments. Therefore, this work should be 

considered only a part of a larger discussion of future research priorities associated with 

firefighter safety. The assessment discussed by Page et al. (In review) concluded that firefighter 

entrapments continue to occur in part due to the inability of firefighters to anticipate rapid 

increases in fire behavior that are caused by changes in the fire environment that happen over 

small spatial and temporal scales. To address this issue we developed a list of several items that 

should be investigated to enhance both fundamental knowledge and the tools used to disseminate 

that knowledge to improve wildland firefighter situational awareness. 

Inadequate knowledge

With regards to the prediction of extreme fire behavior, we echo the research needs presented by 

Werth et al. (2011, 2016), which include a better understanding of plume dynamics and its 

effects on spotting, improvements in measuring and representing complex fuel structure, more 

observations of windflow in complex terrain to improve or create better wind models, an 

understanding of how ambient winds and topography affect fire interactions and additional 

research to quantify the effects of atmospheric stability on fire behavior. We also acknowledge 

the recommendations by Butler (2015) who suggested that additional research is needed to 

address; (1) how convective energy affects safety zone size, (2) how clothing affects the 

likelihood of burn injury, (3) better information on travel rates over complex terrain, (4) 

methods to integrate escape route travel times into safety zone assessments, (5) a better 

understanding of the effectiveness of bodies of water as safety zones, (6) knowledge as to how 

firefighters can determine if an area is survivable and (7) methods firefighters can use to apply 

safety zone standards.

Additional knowledge gaps that were found to be important in this review were:
17

 A better identification of the environmental factors that lead to rapid increases in fire 

behavior including important interactions and their relative influences. 

 The development of fire behavior models capable of anticipating the times and 

locations where rapid increases in spread rate and intensity are possible. 

 Methods for improving crew situational awareness regarding changes in weather, fire 

location and the best available escape routes. 

 And, improved NWP models and weather forecasts that provide high resolution, 

spatially-explicit information on the timing and influence of thunderstorms and other 

high-wind events on near-surface wind speed and direction. Ideally, forecasts should 

have lead times of at least 12-16 h so that incident plans could be altered before the 

start of an operational period. 

Inadequate tools

Several issues regarding the inadequacy of the current set of tools for anticipating or identifying 

the conditions that affect entrapment potential were identified based on an analysis of needs 

related to four of the standard firefighting orders that directly relate to the environmental and fire 

behavior factors commonly associated with entrapments (Table 2). A complete catalog of these 

tools including their purpose, spatial and temporal resolutions, and operating platforms can be 

found in Page et al. (In Review). 

Generally, the assessment in Table 2 suggests that in addition to better information 

on how firefighters utilize or do not utilize fire behavior prediction tools, including preferences 

on capabilities, format and organization, future tools should:

 Provide updated fire environment information, including fire position, at hourly or subhourly intervals (i.e. near real-time) so that firefighters can better anticipate the changes 

that lead to extreme fire behavior (Wall et al. 2018). 

 And, have the ability to merge the updated information with firefighter/equipment 

locations in relation to safety zones and escape routes, in order to develop a 

comprehensive system similar to the one proposed by Gabbert (2013), i.e. the “Holy 

Grail of Firefighter Safety”. 
18

Table 2. Some of the current tools and their limitations related to 4 of the standard firefighting orders.

1. Keep informed on fire weather conditions and forecasts.

 Current tools

A whole suite of websites and mobile applications currently provide information on the 

various weather, fire danger, and climate variables that are important for assessing fire 

behavior potential (see Page et al. In review).

 Limitations Few have the ability to provide a comprehensive set of weather-related information at the 

spatial and temporal scales most relevant to wildland firefighters.

2. Know what your fire is doing at all times.

 Current tools

Various platforms can provide information on fire position based on satellite detections 

(https://firms.modaps.eosdis.nasa.gov/map/#z:3;c:0.0,0.0;d:2019-04-03..2019-04-04), 

infrared interpretation (https://www.nifc.gov/NIICD/infrared/phoenix_capabilities.html), 

and locally near real-time with drones or infrared cameras in aircraft.

 Limitations

Very few of these technologies can provide near real-time information on fire position. 

Those that can are usually limited by aircraft restrictions and the ability to conveniently

transfer and display the data to firefighters.

3. Base all actions on current and expected behavior of the fire.

 Current tools

Numerous fire behavior prediction tools are available to predict fire behavior. Some have 

also been distilled into tabular, graphical or mobile application formats (see Page et al. In 

Review). 

 Limitations Many fire behavior models cannot currently run faster than real-time and rapidly 

incorporate updated fire environment information in a field setting.

4. Identify escape routes and safety zones and make them known.

 Current tools

Some guidelines currently exist to aid in the identification of escape routes and safety 

zones (NWCG 2018). A new mobile web application (https://wise.wildfireanalyst.com/) 

can provide site specific information on safety zone size.

 Limitations There are not currently any tools available that can provide real-time, site specific 

information on escape route effectiveness in a field setting.

Improved data collection and storage

In order to continue improving our knowledge of the factors that affect firefighter entrapments 

and produce better quality tools, a centralized data repository that contains updated information 

on the details associated with past incidents is needed. Although several storage systems already 

exist, each of these have significant shortcomings. 

We have presented a database recently compiled by the authors that provides many of 

the details that have been excluded from previous storage systems. It is hoped that a similar 

database could be maintained and updated in a central location so that other researchers could 

access the data. Besides the information technology required to support such a system, we have 

identified additional data collection and quality issues that are needed to fully capture the details 

of each entrapment incident. Specifically, an unacceptably high proportion of investigative type 

documents and reports of firefighter entrapments either fail to include or fail to adequately 

summarize the relevant environmental factors associated with each incident. In order to facilitate 

data collection and storage we recommend that future entrapment investigations explicitly 

include summaries containing information on all of the relevant fire environment factors in a 

non-narrative format (Table 3). 
19

Table 3. Recommended minimum data collection and reporting standards for the relevant fire 

environment variables associated with firefighter entrapments that involve a burnover or are considered a 

near-miss. It is suggested that the measurements be made at or immediately adjacent to the burnover 

location. The measurement location for a near-miss may not be obvious, so best judgement is 

recommended.

Factor Comments

Fuels

 Fuel type Fuel type should be reported based on the 6 broad categories described 

by Scott and Burgan (2005). If live fuels are involved, provide a brief 

description of the species and any unique characteristics (e.g. dead 

material in crown or fuel age).

 Fuel height Estimated height of vegetation that was burning in or immediately 

adjacent to the entrapment area.

 Dead fuel moisture Estimated or measured moisture content of dead surface fuels, 

preferably reported as % of oven-dry weight. Include estimates for all 

applicable size classes (i.e. fine fuels or larger).

 Live fuel moisture Estimated or measured live fuel moisture content, preferably reported 

as % of oven-dry weight.

 How fuel variables were 

 assessed

Description of methods used to estimate or measure the reported fuel 

characteristics.

Weather 

 Temperature Estimated or recorded air temperature at/near entrapment site prior to 

the burnover. The value should reflect the air temperature that is not 

influenced by the fire and should be reported at a time that is as close 

to the entrapment time as feasible.

 Relative humidity Estimated or recorded relative humidity at/near entrapment site prior to 

the burnover. The value should reflect the relative humidity that is not 

influenced by the fire and should be reported at a time that is as close 

to the entrapment time as feasible.

 Wind speed Temporally averaged wind speed that was recorded or estimated 

at/near entrapment site prior to burnover. Include averaging period (i.e. 

5 or 10 min) and applicable reference height and exposure (e.g. instand eye-level or 6 m open). Measurement should be free of influence 

from the fire. See Andrews (2012) for an in-depth discussion. Note 

any changes in wind speed during the preceding 1 to 2 hours before the 

entrapment.

 Wind direction Temporally averaged wind direction that was recorded or estimated 

at/near entrapment site prior to burnover. Include averaging period (i.e. 

5 or 10 min) and applicable reference height and exposure (i.e. eyelevel or 6 m). Measurement should be free of influence from the fire. 

See Andrews (2012) for an in-depth discussion. Note any changes in 

wind direction during the preceding 1 to 2 hours before the 

entrapment.

 Measurement source/quality Description of methods used to estimate or measure the weather 

characteristics, including models or websites used and weather station 

location and name.

Topography
20

 Slope steepness Slope steepness at the entrapment site and measurement method. 

Consider reporting slope steepness measured upwind from the 

entrapment site if it is significantly different.

 Terrain description Provide brief description of the dominate terrain characteristics around 

the entrapment location, including descriptions of terrain shape (e.g. 

canyons).

Refuge area

 Location Provide latitude and longitude of entrapment location(s) as reported by 

a Global Positioning System.

 Physical dimensions Include a sketch or diagram of the entrapment area that contains 

locations of personnel and equipment as well as distances from terrain 

and vegetation features.

 Separation distance between 

 firefighters and flame zone

Distance between firefighters and flame zone during the burnover.

Escape route(s)

 Travel route(s) of firefighters Travel route followed by firefighters from work area to entrapment 

area. Preferably shown on a map or as a GPS track with photos of trail 

quality.

Fire behavior

 Rate of spread Observed or estimated spread rate of fire before and during the 

entrapment. Note any significant temporal variation in the 1-2 h before 

entrapment.

 Flame length / height Observed or estimated flame characteristics before and during the 

entrapment. Note any significant temporal variation in the 1-2 h before 

entrapment.

 General fire behavior General notes on fire behavior including fire type (surface versus 

crown fire), spotting activity and any significant temporal variations 

leading up to the entrapment. Provide photos and video footage of fire 

behavior with time stamps whenever possible.

 How estimates were 

 obtained

Details associated with how fire behavior estimates were either 

measured or modelled. If fire behavior was measured, include 

appropriate details.

Other

 Approximate date and time 

 of burnover 

Date and time that the entrapment occurred, including time zone.

 Safety Zones Locations of any planned safety zones, particularly in relation to the 

escape route utilized.

 Fire size Estimated fire size at the time of entrapment.

 Equipment involved Description of any equipment involved and their location within the 

entrapment area. Include details associated with the use of the 

equipment as a shield or accessories such as fire curtains. 

 Photographic evidence Photographs and video footage of the entrapment location. Consider 

the use of high resolution ground or aerial-based laser ranging 

(LIDAR) equipment to capture 3-D point clouds of entrapment 

location and surrounding area; see Loudermilk et al. (2009) for 

examples.
21

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A1

Appendix A: Contact Information

W. Matt Jolly, USDA Forest Service, Rocky Mountain Research Station, 5775 W Highway 10, 

Missoula, MT 59808; matt.jolly@usda.gov; (406) 329-4848 

Bret Butler, USDA Forest Service, Rocky Mountain Research Station, 5775 W Highway 10, 

Missoula, MT 59808; bret.butler@usda.gov; (406) 329-4801

Patrick Freeborn, USDA Forest Service, Rocky Mountain Research Station, 5775 W Highway 

10, Missoula, MT 59808; patrick.h.freeborn@usda.gov; (406) 329-4823

Wesley Page, USDA Forest Service, Rocky Mountain Research Station, 5775 W Highway 10, 

Missoula, MT 59808; wesley.g.page@usda.gov; (435) 421-1686 
A2

Appendix B: List of Products

Online firefighter entrapment database (1979-2018)

See https://www.wfas.net/entrap/.

Articles in peer-reviewed journals

Jolly WM, Freeborn PH, Page WG, Butler BW. A wildfire early warning system to reduce 

wildland firefighter and community risk during extreme wildfire events. (manuscript in 

preparation)

Page WG, Freeborn PH, Butler BW, Jolly WM. A review of US wildland firefighter 

entrapments: trends, important environmental factors and research needs. International Journal 

of Wildland Fire (manuscript accepted pending revision)

Other published materials

Page WG, Freeborn PH (In Press) Entrapment. ‘Encyclopedia of Wildfires and Wildland-Urban 

Interface (WUI) Fires’. (Ed SL Manzello) Springer Nature. (New York, NY, USA)