Technical Support Document

For the March 22, 2009

Pagosa Springs Exceptional Event

Prepared by the Technical Services Program

Air Pollution Control Division

Colorado Department of Public Health and 

Environment

March 30, 2012
Table of Contents

1.0 Introduction.......................................................................................................................................5

PM10 Standards..........................................................................................................................................5

Event Overview.........................................................................................................................................5

2.0 Meteorological Analysis of the March 22, 2009, Blowing Dust Event ............................................8

3.0 Ambient Monitoring Data and Statistics.........................................................................................47

Section 3.1 Historical Fluctuations of PM10 Concentrations Pagosa Springs.........................................58

Pagosa Springs ........................................................................................................................................60

No Exceedance But For the Event ..........................................................................................................63

Section 3.2 Monitoring Data and Conclusions........................................................................................63

4.0 News Accounts and Credible Evidence ..........................................................................................64

5.0 Local Dust Control..........................................................................................................................75

6.0 Laboratory and Field Data ..............................................................................................................77

7.0 Summary and Conclusions..............................................................................................................80

8.0 References.......................................................................................................................................82

Figures

Figure 1. 24-hour PM10 concentrations in μg/m3for March 22, 2009. ........................................................9

Figure 2. Surface analysis for 12Z March 22, 2009, or 5 AM MST March 22, 2009 ..............................10

Figure 3. Surface analysis for 06Z March 23, 2009, or 11 PM MST March 22, 2009 .............................11

Figure 4. 500 mb analysis for 12Z March 22, 2009, or 5 AM MST March 23, 2009 ...............................12

Figure 5. 500 mb analysis for 00Z March 23, 2009, or 5 PM MST March 23, 2009 ................................12

Figure 6. Flagstaff, Arizona sounding analysis for 00Z March 23, 2009 or 5 PM MST March 22, 2009.13

Figure 7. Albuquerque, New Mexico sounding analysis for 00Z March 23, 2009 or 5 PM MST March 22, 

2009 . ..........................................................................................................................................................13

Figure 8. Grand Junction, Colorado sounding analysis for 00Z March 23, 2009 or 5 PM MST March 22, 

2009 . ..........................................................................................................................................................14

Figure 9. Wind directions and gust speeds in dust source regions and the Pagosa Springs area at 18:31Z 

March 22, 2009 or 11:31 AM MST on March 22, 2009 . ..........................................................14

Figure 10. Wind directions and gust speeds in dust source regions and the Pagosa Springs area at 23:31Z 

March 22, 2009 or 4:31 PM MST on March 22, 2009 ...............................................................15

Figure 11. Streamlines from the NOAA NCEP North American Model with 12 kilometer grid spacing at 

0Z March 23, 2009 (5 PM MST March 22). Only wind speeds above 25 mph are contoured..18

Figure 12. Percent of Normal Precipitation 3/1/2009 – 3/31/2009, source High Plains Regional Climate 

Center .........................................................................................................................................................19

Figure 13. Percent of Normal Precipitation 1/1/2009 – 3/31/2009, source High Plains Regional Climate 

Center .........................................................................................................................................................19

Figure 14. Calculated Soil Moisture Anomaly for March 2009 ................................................................20

Figure 15. Calculated Soil Moisture Anomaly for February 2009 ............................................................20

Figure 16. Drought status for the Colorado on March 24, 2009 ................................................................21

Figure 17. NOAA HYSPLIT 24-hour back trajectories for Pagosa Springs Colorado for each hour from 1 

AM MST to Midnight MST on March 22, 2009.. ......................................................................22

Figure 18. NOAA HYSPLIT MODEL Matrix area for HYSPLIT Matrix forward trajectories. ..............23
Figure 19. NOAA HYSPLIT 24-hour forward matrix trajectories for 15Z March 22, 2009, or 8 AM MST 

March 22, 2009...........................................................................................................................24

Figure 20. NOAA HYSPLIT 24-hour forward matrix trajectories for 18Z March 22, 2009, or 11 AM 

MST March 22, 2009..................................................................................................................25

Figure 21. NOAA HYSPLIT 24-hour forward matrix trajectories for 21Z March 22, 2009, or 2 PM MST 

March 22, 2009...........................................................................................................................26

Figure 22. NOAA HYSPLIT 24-hour forward matrix trajectories for 00Z March 23, 2009, or 5 PM MST 

March 22, 2009...........................................................................................................................27

Figure 23. Dodge City sounding analysis for 12Z March 22, 2009, or 5 AM MST March 22, 2009. ......28

Figure 24. Wind directions and gust speeds caused by low-level jet over the Great Plains at 7:47Z March 

22, 2009 or 12:47 AM MST on March 22, 2009........................................................................39

Figure 25. Friction velocities in meters/second from the NOAA NCEP North American Model with 12 

kilometer grid spacing at 6Z March 22, 2009...........................................................................39

Figure 26. Friction velocities in meters/second from the NOAA NCEP North American Model with 12 

kilometer grid spacing at 12Z March 22, 2009.........................................................................40

Figure 27. Friction velocities in meters/second from the NOAA NCEP North American Model with 12 

kilometer grid spacing at 18Z March 22, 2009.........................................................................40

Figure 28. Friction velocities in meters/second from the NOAA NCEP North American Model with 12 

kilometer grid spacing at 0Z March 23, 2009...........................................................................41

Figure 29. Dust-on-Snow Deposition Events Log at the Senator Beck Basin Study Area on Red Mountain 

Pass, Colorado...........................................................................................................................43

Figure 30. MODIS satellite image centered on Arizona at 21:18Z March 22, 2009 ................................44

Figure 31. Smoke Text Product Satellite Services Division, Descriptive Text Narrative for Smoke/Dust 

observed in satellite imagery through 0045Z March 22, 2009 .................................................45

Figure 32. NAAPS forecasted dust concentrations for March 22, 2009....................................................46

Figure 33. PM10 Seasonal Concentrations in Pagosa Springs March and April, 2009. .............................49

Figure 34. PM10 Annual Concentrations in Pagosa Springs during 2009..................................................51

Figure 35. Five Year Time-Series Graph of PM10 in Pagosa Springs........................................................52

Figure 36. PM10 Seasonal Concentrations in Mount Crested Butte, March and April, 2009. ...................53

Figure 37. PM10 Seasonal Concentrations in Lamar, March and April, 2009. ..........................................54

Figure 38. PM10 Seasonal Concentrations in Steamboat Springs, March and April, 2009........................55

Figure 39. PM10 Annual Concentrations in Mount Crested Butte during 2009.........................................56

Figure 40. PM10 Annual Concentrations in Lamar during 2009. ...............................................................57

Figure 41. PM10 Annual Concentrations in Steamboat Springs during 2009. ...........................................58

Figure 42. Pagosa Springs PM10 Histogram. ...........................................................................................61

Figure 43. Monthly Pagosa Springs PM10 Box and Whisker Plot. ............................................................61

Figure 44. Annual Pagosa Springs PM10 Box and Whisker Plot. ..............................................................62

Figure 45. March 23, 2009, email from Lee Cassin, the Environmental Manager for Pitkin County, 

Colorado......................................................................................................................................................65

Figure 45 a. Response to Cassin email. .....................................................................................................66

Figure 46. Mt. Crested Butte Town Manager description of the event......................................................67

Figure 47. Dust on vehicle in Aspen, Colorado, after the March 22, 2009 dust storm, from Lee Cassin. 68

Figure 48. Dust on snow in Aspen, Colorado, after the March 22, 2009 dust storm, from Lee Cassin ....69

Figure 49. Dust on vehicle in Aspen, Colorado, after the March 22, 2009 dust storm..............................70

Figure 50. Aspen Times staff report. .........................................................................................................71

Figure 51. Vail Daily news article. ............................................................................................................72

Figure 52. Aspen Times dust article. .........................................................................................................73

Figure 53. National Operational Hydrologic Remote Sensing Center modeled snow cover for area near 

Aspen, Colorado for 00Z March 23, 2009 or 5 PM March 22, 2009........................................74
Tables

Table 1. Wind and weather observations for Sandoval Mesa, Colorado ...................................................29

Table 2. Wind and weather observations for Hayden, Colorado ...............................................................30

Table 3. Wind and weather observations for Alamosa, Colorado .............................................................31

Table 4. Wind and weather observations for Durango, Colorado..............................................................32

Table 5. Wind and weather observations for Lamar, Colorado .................................................................33

Table 6. Wind and weather observations for Farmington, New Mexico ...................................................34

Table 7. Wind and weather observations for Gallup, New Mexico...........................................................35

Table 8. Wind and weather observations for Kykotsmovi Village, Arizona .............................................36

Table 9. Wind and weather observations for Window Rock, Arizona ......................................................37

Table 10. Wind and weather observations for Winslow, Arizona .............................................................38

Table 11. Pagosa Springs PM10 Concentrations Before and After March 22, 2009 Regional Dust Storm. 47

Table 12. PM10 Monitoring Data Summary for Pagosa Springs................................................................59

Table 13. PM10 Monitoring Data Percentiles of Frequency for Other Areas with Elevated PM10 ............59

Table 14. Pagosa Springs Month and Year PM10 Monitoring Data Summary. .........................................60

Table 15. Estimation of event PM10 totals for Pagosa Springs. .................................................................63

Attachments

Attachment A - Grand Junction, Colorado, Blowing Dust Climatology. ...................................................83

Attachment B - Southwest Surface Analysis............................................................................................106

Attachment C - Hourly Surface Streamlines.............................................................................................112

Attachment D - Weather Warnings and Advisories from the National Weather Service Forecast Offices in

Grand Junction, Colorado, Flagstaff, Arizona, and Albuquerque, New Mexico for March 22, 2009......123
5

1.0 Introduction

PM10 Standards

In July 1987, EPA promulgated National Ambient Air Quality Standards for Particulates with an 

aerodynamic diameter of 10 microns or less (PM10). This is a size range that can affect the upper airways 

and can be inhaled into the alveolar regions of the lungs. The standard has one form, a 24-hour standard 

of 150 μg/m3. The annual arithmetic mean standard of 50 μg/m3 was revoked on October 17, 2006. The 

24-hour standard is attained when the expected number of exceedances for each calendar year, averaged 

over three years, is less than or equal to one. The estimated number of exceedances is computed quarterly 

using available data and adjusting for missing sample days. A data recovery of 75 percent is needed for 

each calendar quarter to be considered a valid quarter of data. This standard was modified in by EPA in 

July 1997, but was subsequently nullified back to this form in May 1999.

Event Overview

On Sunday March 22, 2009, Pagosa Springs, Colorado, recorded an exceedance of the twenty-four-hour 

PM10 standard with a concentration of 255 μg/m3at the Pagosa Springs monitor. The Colorado 

Department of Public Health and Environment (CDPHE) Air Pollution Control Division (APCD) has 

prepared this report for the U.S. Environmental Protection Agency (EPA) to demonstrate that the elevated 

PM10 concentrations in Pagosa Springs and other areas of Colorado and the exceedance of the National 

Ambient Air Quality Standard (NAAQS) for PM10 at Pagosa Springs were caused by a natural event, 

specifically a dust storm. It will be shown that this exceedance and the high PM10 readings are the 

consequence of a dust storm in the Four Corners area. This event meets the criteria outlined by the final 

―Treatment of Data Influenced by Exceptional Events‖ Rule (72 FR 13560). This report and the analysis 

and data contained within it show that this exceptional event passed the four required tests (a) through (d) 

under 40 CFR 50.14 (3)(iv). These tests are: 

(a) The event satisfies the criteria set forth in 40 CFR 50.1(j) which requires that an exceptional 

event ―affects air quality, is not reasonably controllable or preventable...‖ and that such events are 

―...natural event[s]‖. 

(b) There is a clear causal relationship between the measurement under consideration and the event 

that is claimed to have affected the air quality in the area.

(c) The event is associated with a measured concentration in excess of normal historical fluctuations, 

including background; and

(d) There would have been no exceedance or violation but for the event. 

Elevated 24-hour PM10 concentrations were recorded across much of Colorado on March 22, 2009. 

Except for the readings in the Denver metropolitan area, all of the March 22 twenty-four-hour PM10

concentrations were above the 90th percentile concentrations for their locations. The Pagosa Springs 

concentration exceeds the 99th percentile, and a conservative estimate of the dust storm contribution to 

the total concentration is 199-211 μg/m3. This is evidence that the event was associated with a measured 

concentration in excess of normal historical fluctuations including background. But for the dust storm to 

be described in detail in this report, there would have been no exceedance on this day in Pagosa Springs.

This exceedance was the consequence of strong southwesterly winds in combination with dry conditions 

which caused significant blowing dust across much of northeast Arizona, northwest New Mexico, and 

southwest Colorado. These winds were partly the result of a developing low pressure over the Great 

Basin and strong winds aloft which mixed down to the surface in the deeply-mixed surface boundary 

layer. Surface weather analyses show an area of low pressure affecting the Four Corners region. The 

pressure gradient around the low contributed to strong gusty surface winds across much of Arizona, 
6

northwest New Mexico, and southwest Colorado. Surface winds of 20 to 50 mph with gusts of 25 to 62 

mph were recorded across the Four Corners region on March 22. These speeds are above the thresholds 

for blowing dust identified in EPA draft guidance and in detailed analyses completed by the State of 

Colorado.

EPA‘s May 2, 2011 draft Guidance on the Preparation of Demonstrations in Support of Requests to 

Exclude Ambient Air Quality Data Affected by High Winds under the Exceptional Events Rule states 

―Empirical evidence shows that a sustained wind speed of 25 mph is typically the minimum wind speed 

needed to entrain particles from many stable surfaces ...‖ In addition, in both eastern and western 

Colorado it has been shown that wind speeds of 30 mph or greater and gusts of 40 mph or greater can 

cause blowing dust (see references for the Natural Events Action Plan for High Wind Events – Lamar, 

Colorado and the Technical Support Document for the January 19, 2009 Lamar Exceptional Event and 

Attachment A - Grand Junction, Colorado, Blowing Dust Climatology at the end of this document). For 

this blowing dust event, it has been assumed that sustained winds of 25 mph and higher or wind gusts of

40 mph and higher can cause blowing dust in northeast Arizona, northwest New Mexico, and southwest 

Colorado.

Climatological data for March shows that most of the Four Corners area had received less than 50 

percent of the normal precipitation for the month and northeast Arizona was abnormally dry. Hopi in 

northeastern Arizona received only 0.17 inches of precipitation during the 30 days prior to March 22. 

This total is well below the approximate threshold for blowing dust conditions at Hopi identified in the 

analysis contained in Attachment A. Both wind speeds and soil moisture in the Four Corners area and 

northeastern Arizona were conducive to the generation of significant blowing dust.

Friction velocities calculated for the region also help to explain why blowing dust originated in the Four 

Corners region and northeastern Arizona in particular. Friction velocities are a function of wind speed, 

surface roughness, and the change in wind speeds with height above the ground surface. Threshold 

friction velocities vary with soil type and land cover and are a measure of the minimum conditions 

necessary for suspension of soil particles in wind. According to Marticorena and coauthors (1997), even 

undisturbed desert soils normally resistant to wind erosion will be susceptible to blowing dust when 

friction velocities are greater than about 1.0 to 2.0 meters per second. A wide area of Arizona and New 

Mexico had friction velocities well above 1.0 meters per second late in the day. Some of the highest 

values were within the Little Colorado River Valley and Painted Desert region of northeast Arizona. 

Note that blowing dust will typically only occur where these values are high and the soils are dry and not 

protected by vegetation, forest cover, boulders, rocks, etc. This is why blowing dust occurred in the 

desert areas of northeast Arizona and northwest New Mexico on March 22, 2009. The computed friction 

velocities, measured wind speeds, and data on soil moisture conditions prove that this dust storm was a 

natural event that was not reasonably controllable or preventable.

Satellite imagery shows large plumes of southwest to northeast trending blowing dust in the Painted 

Desert and Little Colorado River Valley region of northeastern Arizona on March 22. Forward and 

backward trajectories, wind streamline analyses, and surface and upper-level wind patterns show that this 

dust would have been transported into Colorado on March 22. An analysis run of a high-resolution 

meteorological model also shows winds flowing across northeast Arizona and northwest New Mexico 

into Colorado. This analysis indicates that the zone of highest speeds targeted the Painted Desert and 

Little Colorado Valley areas of northeastern Arizona – areas shown in Attachment A to be a significant 

source region for blowing dust transported into Colorado. Multiple sources of data and analyses of past 

dust storms in this area prove that this was a natural event and, more specifically, a significant natural 

dust storm originating in northeastern Arizona and northwestern New Mexico. But for the dust storm on 

March 22, 2009, this exceedance would not have occurred.
7

The Center for Snow and Avalanche Studies (http://www.snowstudies.org/index.html) has been studying 

the effects of desert dust deposition on snowpack albedo and snowmelt in the San Juan Mountains of 

Colorado. The center‘s log of events lists March 22, 2009, as one of twelve Dust-on-Snow events for the 

2008/2009 water year. Reports and photos from Pitkin County Environmental Health staff and other data 

indicate that desert dust from the Four Corners region moved as far north as Aspen, Colorado, during the 

evening of March 22. NOAA‘s Satellite Service Division also describes blowing dust moving from 

Arizona into southwest Colorado on March 22, 2009. Multiple reports from professional experts at other 

institutions substantiate the conclusion that this was a natural event. But for the dust storm on March 22, 

2009, this exceedance would not have occurred.
8

2.0 Meteorological Analysis of the March 22, 2009, Blowing 

Dust Event

On Sunday March 22, 2009, Pagosa Springs Colorado recorded an exceedance of the twenty-four-hour 

PM10 standard with a concentration of 255 μg/m3at the Pagosa Springs monitor. Elevated readings were 

recorded across much of Colorado as shown in Figure 1. Except for the readings in the Denver 

metropolitan area, all of these twenty-four-hour PM10 concentrations in Colorado were above the 90th

percentile concentrations for their locations. The Pagosa Springs concentration exceeds the 99th

percentile, and a conservative estimate of the dust storm contribution to the total concentration is 199-

211 μg/m3. This is evidence that the event was associated with a measured concentration in excess of 

normal historical fluctuations including background. 

This exceedance was the consequence of strong southwesterly winds in combination with dry conditions 

which caused significant blowing dust across much of northeast Arizona, northwest New Mexico, and 

southwest Colorado. These winds were partly the result of a developing low pressure over the Great 

Basin. The surface analysis for 12Z March 22 (5AM MST March 22) presented in Figure 2 shows a 

broad area of low pressure from Nevada to southeast Montana. This area of low pressure would 

strengthen and become the 988 milibar low centered over eastern Colorado shown in the 06Z March 23, 

(11 PM MST March 22) surface analysis in Figure 3. The pressure gradient around the low contributed to 

the strong gusty surface winds across much of Arizona, northwest New Mexico, and southwest Colorado.

These surface features were associated with a strong upper level trough digging into the western U.S. 

Figure 4 shows the 500 milibar analysis (at roughly 18,000 feet above sea level) for 12Z March 22, 2009

(5AM MST March 22). The winds on the east side of the trough over much of the southwestern portion 

of the United States were generally 40 knots with a speed maximum of 90 knots over southern California. 

Strong winds extended from just above the surface inversion to about 500 milibars. Once the morning 

inversion had dissipated, the momentum associated with the strong winds above the inversion mixed 

down to the surface, intensifying the surface winds induced by the surface pressure gradient in Figures 2 

and 3. In Figure 5, the 500 milibar analysis for 00Z March 23, 2009 (5 PM MST March 22) shows that 

the trough had moved east and the speed maximum was over Arizona with a wind speed of 85 knots. 

The 00Z March 23, 2009 (5 PM MST March 22) soundings from Flagstaff, Arizona, Albuquerque, New 

Mexico, and Grand Junction, Colorado, in Figures 6 through 8, respectively, bracket the area that 

experienced the strong gusty surface winds on March 22, 2009. They show good vertical mixing to near 

500 milibars. Wind speeds in the mixed layer (surface boundary layer) ranged from 30 to 60 knots. The 

combination of the mixing and the tight surface pressure gradient caused surface winds of 20 to 50 mph 

with gusts of 25 to 62 mph. These winds can be seen in the MesoWest surface analysis of the Four 

Corners area for 18:31Z March 22, 2009 or 11:31 AM MST, and 23:31Z March 22, 2009 or 4:31 PM 

MST in Figures 9 and 10 (from http://www.met.utah.edu/mesowest/). 

EPA‘s May 2, 2011 draft Guidance on the Preparation of Demonstrations in Support of Requests to 

Exclude Ambient Air Quality Data Affected by High Winds under the Exceptional Events Rule states 

―Empirical evidence shows that a sustained wind speed of 25 mph is typically the minimum wind speed 

needed to entrain particles from many stable surfaces (i.e., undisturbed/natural surfaces with a crust or 

disturbed surfaces that have been restabilized) in the western U.S. where rainfall is seasonal (see 

Appendix A), and thus is a useful threshold for setting differential expectations for the detail to be 

included in a demonstration that dust from a wind event was not reasonably controllable or preventable.‖ 

In addition, in both eastern and western Colorado it has been shown that wind speeds of 30 mph or greater 

and gusts of 40 mph or greater can cause blowing dust (see references for the Natural Events Action Plan 

for High Wind Events – Lamar, Colorado and the Technical Support Document for the January 19, 2009
9

Lamar Exceptional Event and Attachment A - Grand Junction, Colorado, Blowing Dust Climatology at 

the end of this document). For this blowing dust event it is assumed that sustained winds of 25 mph and 

higher or wind gusts of 40 mph and higher can cause blowing dust in northeast Arizona, northwest New 

Mexico and southwest Colorado. Figures 2 through 10 show that the conditions necessary for strong 

gusty winds were in place over the area of concern for the daytime hours of March 22, 2009. 

 

Figure 1. 24-hour PM10 concentrations in μg/m3for March 22, 2009.
10

Figure 2. Surface analysis for 12Z March 22, 2009, or 5 AM MST March 22, 2009 (from National 

Weather Service fax maps http://nomads.ncdc.noaa.gov/ncep/NCEP).
11

Figure 3. Surface analysis for 06Z March 23, 2009, or 11 PM MST March 22, 2009 (from National 

Weather Service fax maps http://nomads.ncdc.noaa.gov/ncep/NCEP).
12

Figure 4. 500 mb analysis for 12Z March 22, 2009, or 5 AM MST March 23, 2009 (from National 

Weather Service fax maps http://archive.atmos.colostate.edu/).

Figure 5. 500 mb analysis for 00Z March 23, 2009, or 5 PM MST March 23, 2009 (from National 

Weather Service fax maps http://archive.atmos.colostate.edu/).
13

Figure 6. Flagstaff, Arizona sounding analysis for 00Z March 23, 2009 or 5 PM MST March 22, 2009 

(http://weather.uwyo.edu/upperair/sounding.html).

Figure 7. Albuquerque, New Mexico sounding analysis for 00Z March 23, 2009 or 5 PM MST March 22, 

2009 (http://weather.uwyo.edu/upperair/sounding.html).
14

Figure 8. Grand Junction, Colorado sounding analysis for 00Z March 23, 2009 or 5 PM MST March 22, 

2009 (http://weather.uwyo.edu/upperair/sounding.html).

Figure 9. Wind directions and gust speeds in dust source regions and the Pagosa Springs area at 18:31Z 

March 22, 2009 or 11:31 AM MST on March 22, 2009 (http://www.met.utah.edu/mesowest/).
15

Figure 10. Wind directions and gust speeds in dust source regions and the Pagosa Springs area at 23:31Z 

March 22, 2009 or 4:31 PM MST on March 22, 2009 (http://www.met.utah.edu/mesowest/).

The Service Records Retention System (SRRS) is an archive and access system for selected National 

Weather Service (NWS) operational products maintained at the National Climatic Data Center (NCDC). 

Copies of the Southwest Surface Analysis from SRRS for 06Z March 22, 2009 (11 PM MST March 21) 

to 06Z March 23, 2009 (11 PM MST March 22) are presented in Attachment B. They show the cold front 

moving across the Southwest U.S. with strong southwest winds ahead of the cold front. The Surface 

Streamline Analyses for 12Z March 22, 2009 (5 AM MST March 22) through 06Z March 23, 2009 (11 

PM MST March 22) are presented in Attachment C. These show southerly to southwesterly surface 

winds in northeast Arizona and northwest New Mexico flowing into Colorado beginning at 18Z March 

22, 2009 (11 AM MST March 22) and continuing until 06Z March 23, 2009 (11 PM MST March 22). 

Figure 11 shows the surface (10-meter height) streamline analysis for 0Z March 23, 2009 (5PM MST 

March 22). This plot is based on the analysis-only model run of the NOAA National Center for 

Environmental Prediction (NCEP) North American Model with 12 kilometer grid spacing (NAM12) 

based on current observations and high-resolution physics 

(http://nomads.ncdc.noaa.gov/data.php?name=access#hires_weather_datasets). 

The NAM12 analysis also shows the winds flowing across northeast Arizona and Northwest New Mexico 

into Colorado. The analysis for this time period shows that speeds above blowing dust thresholds and 

greater than 30 mph were largely confined to the Painted Desert and Little Colorado River Valley areas of 

northeastern Arizona – areas shown in Attachment A to be a significant source region for blowing dust 

transported into Colorado.

Figure 12 Shows the Percent of Normal Precipitation for the southwest U.S. during March 2009. Most of 

the area to the southwest of Pagosa Springs had less than 50 percent of normal precipitation. This lack of 

precipitation was not limited to March. The region had been abnormally dry since January of 2009 as 

illustrated in Figure 13. March of 2009 saw below normal soil moisture levels across the region as seen 

in Figure 14. Figure 15 shows that the dry soils of March represent an intensification of the dryness from 
16

soil moisture levels in February. The Drought Monitor for March 24, 2009 in Figure 16 shows that much 

of northeast Arizona was classified as having Abnormally Dry conditions. In addition, Hopi, Arizona 

received only 0.17 inches of precipitation during the 30 days prior to March 22, 2009 (0.17 inches fell on 

March 12, 2009 (http://www.raws.dri.edu/cgi-bin/rawMAIN.pl?azAHPI). This total is well below the 

approximate threshold for blowing dust conditions at Hopi identified in Attachment A.

Figure 17 presents the 24-hour back trajectories from the NOAA HYSPLIT model using high-resolution 

NAM12 meteorological input data (http://ready.arl.noaa.gov/HYSPLIT.php) for Pagosa Springs, 

Colorado, for each hour from 1 AM MST to Midnight MST on March 22, 2009. The back trajectories 

show that the air over Pagosa Springs came from portions of Arizona and New Mexico on March 22, 

2009. The NOAA HYSPLIT Model also has a trajectory matrix option. With this option the model can 

calculate a grid of forward trajectories over a user-defined region on a map. As will be shown later in this 

report, northeast Arizona and northwest New Mexico had considerable blowing dust on March 22, 2009. 

A matrix was created for the NOAA HYSPLIT model that covered this source area and the bounding 

rectangle for the matrix is presented in Figure 18.

Forward trajectories for this matrix for 8 AM, 11 AM, 2 PM, and 5 PM MST on March 22, 2009 are 

presented in Figures 19 through 22, respectively. These trajectories start near the time when mixing 

would begin to bring the momentum of the strong winds above the nighttime inversion to the ground, and 

also include the periods of the day with the greatest mixing and near the end of the daytime mixing. They 

show that during these periods the air flowing over the dust source region of northeast Arizona and 

northwest New Mexico moved into Colorado.

Tables 1 through 10 show the observations for Sandoval Mesa, Colorado (observation near Pagosa 

Springs); Hayden, Colorado (nearest reporting station to Steamboat Springs); Alamosa, Colorado; 

Durango, Colorado; Lamar, Colorado; Farmington, New Mexico; Gallup, New Mexico; Kykotsmovi 

Village, Arizona; Window Rock, Arizona; and Winslow, Arizona respectively. Winds of 25 mph or 

greater, wind gusts of 40 mph or greater, reduced visibility, and the weather type ―haze‖ are highlighted 

in yellow in these tables. These locations are near or in the area covered by the HYSPLIT trajectories. 

Each site except Hayden, the northern most location, had 5 to 11 hours where winds were strong enough 

to cause blowing dust. Hayden had 2 hours of winds that reached blowing dust thresholds. Durango and 

Farmington each had 2 hours during which the visibility was reduced due to dust after the wind speeds 

had dropped below the blowing dust thresholds. This continuation of visibility reductions after such a 

decline in speeds indicates that dust was transported into the area as implied by the trajectories in Figures 

17 and 19 through 22.

Lamar had 5 hours in the early morning with wind speeds or wind gusts at or above blowing dust 

thresholds (see Table 5). These winds were not directly associated with the storm that caused the blowing 

dust later in the day on March 22, 2009. They were caused by a low-level jet that is a common 

occurrence on the Great Plains. This low-level jet is apparent in the 12Z March 22, 2009 (5 AM MST 

March 22) Dodge City, Kansas, sounding presented in Figure 23. There was a 50-knot wind under the 

inversion top. This is at the core of the low-level jet. Note that the low-level jet on the Great Plains is 

more like an elevated sheet of winds that covers a large area than a narrow tube of winds. The reflection 

of the low-level jet on surface winds can be seen in the 7:47Z March 22, 2009 (or 12:47 AM MST) 

MesoWest surface analysis for the eastern plains of Colorado, western Kansas, northeast New Mexico, 

and the panhandles of Texas and Oklahoma in Figure 24. It shows surface winds of 15 to 20 mph and 

wind gusts to 32 mph across the plains.

Lamar also had 6 hours with wind speeds or wind gusts at or above blowing dust thresholds late in the 

day on March 22, 2009 (see Table 5). No visibility restrictions were reported, however, and 24-hour 

concentrations of 48 and 111 μg/m3 were recorded at the Municipal Building and Power Plant sites, 
17

respectively (note that the Power Plant site is at the facility within the fence-line and does not meet 

criteria for monitoring ambient air). Both Figures 14 and 15 show that estimated soil moisture levels in 

southeastern Colorado were near normal during this period. The lower concentrations in Lamar, relative 

to Durango, lower soil moistures, and moderate concentrations continuing on March 23, 2009 at Lamar 

(discussed in Section 3.0) are consistent with the transport of dust into southeastern Colorado (which is 

also supported by the forward trajectories in Figures 21 and 22). Friction velocities calculated for the 

region also help to explain why blowing dust may have originated in the Four Corners region and not in 

eastern and southeastern Colorado.

Friction velocities are a function of wind speed, surface roughness, and the change in wind speeds with 

height above the ground surface. Threshold friction velocities vary with soil type and land cover and are 

a measure of the minimum conditions necessary for suspension of soil particles in wind. In a 1997 paper 

―Factors controlling threshold friction velocity in semiarid and arid areas of the United States‖ 

(Marticorena et al., 1997), the authors characterized the erodibility of both disturbed and undisturbed 

desert soil types. The threshold friction velocity, which is described in detail in this paper, is a measure 

for conditions necessary for blowing dust and is higher for undisturbed soils and lower for disturbed soils.

Friction velocities have been calculated for 6Z, 12Z, and 18Z March 22, 2009, (11 PM MST March 21, 5 

AM March 22, and 11 AM March 22, respectively) and 0Z March 23 (5 PM MST March 22) using the 

North American Regional Reanalysis (NARR) NAM12 model

(http://nomads.ncdc.noaa.gov/data.php?name=access#hires_weather_datasets). These friction velocity 

contour maps are shown in Figures 25 through 28. According to data presented by Marticorena and 

coauthors (1997), even undisturbed desert soils normally resistant to wind erosion will be susceptible to 

blowing dust when friction velocities are greater than about 1.0 to 2.0 meters per second. Figure 28

shows that a wide area of Arizona and New Mexico had friction velocities well above 1.0 meters per 

second late in the day. Some of the highest values were within the Little Colorado River Valley and 

Painted Desert region of northeast Arizona where satellite imagery shows the eruption of large, dense 

plumes of blowing dust. Note that blowing dust will typically only occur where these values are high and 

the soils are dry and not protected by vegetation, forest cover, boulders, rocks, etc. This is why blowing 

dust occurred in the desert areas of northeast Arizona and northwest New Mexico on March 22, 2009. 

The friction velocities shown in Figure 28 and the data on soil moisture conditions presented elsewhere

in this report prove that this dust storm was a natural event that was not reasonably controllable or 

preventable.

Figures 25 through 28 also help to explain the lack of comparable concentrations of blowing dust in 

eastern Colorado and the likely transport of Four-Corners area dust into this part of Colorado.
18

Figure 11. Streamlines from the NOAA NCEP North American Model with 12 kilometer grid spacing at 

0Z March 23, 2009 (5 PM MST March 22). Only wind speeds above 25 mph are contoured.
19

Figure 12. Percent of Normal Precipitation 3/1/2009 – 3/31/2009, source High Plains Regional Climate 

Center (http://www.hprcc.unl.edu/maps/current/index.php?action=update_product&product=TDept).

Figure 13. Percent of Normal Precipitation 1/1/2009 – 3/31/2009, source High Plains Regional Climate 

Center (http://www.hprcc.unl.edu/maps/current/index.php?action=update_product&product=TDept).
20

Figure 14. Calculated Soil Moisture Anomaly for March 2009 (http://www.cpc.ncep.noaa.gov/cgibin/US_Soil-Moisture-Monthly.sh).

Figure 15. Calculated Soil Moisture Anomaly for February 2009 (http://www.cpc.ncep.noaa.gov/cgibin/US_Soil-Moisture-Monthly.sh).
21

Figure 16. Drought status for the Colorado on March 24, 2009 (source: the USDA, NOAA, and the 

National Drought Mitigation Center at: http://drought.unl.edu/dm/archive.html).
22

Figure 17. NOAA HYSPLIT 24-hour back trajectories for Pagosa Springs Colorado for each hour from 1 

AM MST to Midnight MST on March 22, 2009. The HYSPLIT model run was based on data from the 

high-resolution 12-kilometer grid spacing NAM numerical weather model (source: NOAA Air Resources 

Laboratory at: http://ready.arl.noaa.gov/HYSPLIT.php).
23

Figure 18. NOAA HYSPLIT MODEL Matrix area for HYSPLIT Matrix forward trajectories in Figures 

19–22.
24

Figure 19. NOAA HYSPLIT 24-hour forward matrix trajectories for 15Z March 22, 2009, or 8 AM MST 

March 22, 2009. The HYSPLIT model run was based on data from the high-resolution 12-kilometer grid 

spacing NAM numerical weather model. (source: NOAA Air Resources Laboratory at: 

http://ready.arl.noaa.gov/HYSPLIT.php).
25

Figure 20. NOAA HYSPLIT 24-hour forward matrix trajectories for 18Z March 22, 2009, or 11 AM 

MST March 22, 2009. The HYSPLIT model run was based on data from the high-resolution 12-

kilometer grid spacing NAM numerical weather model. (source: NOAA Air Resources Laboratory at: 

http://ready.arl.noaa.gov/HYSPLIT.php).
26

Figure 21. NOAA HYSPLIT 24-hour forward matrix trajectories for 21Z March 22, 2009, or 2 PM MST 

March 22, 2009. The HYSPLIT model run was based on data from the high-resolution 12-kilometer grid 

spacing NAM numerical weather model. (source: NOAA Air Resources Laboratory at: 

http://ready.arl.noaa.gov/HYSPLIT.php).
27

Figure 22. NOAA HYSPLIT 24-hour forward matrix trajectories for 00Z March 23, 2009, or 5 PM MST 

March 22, 2009. The HYSPLIT model run was based on data from the high-resolution 12-kilometer grid 

spacing NAM numerical weather model. (source: NOAA Air Resources Laboratory at: 

http://ready.arl.noaa.gov/HYSPLIT.php).
28

Figure 23. Dodge City sounding analysis for 12Z March 22, 2009, or 5 AM MST March 22, 2009

(http://weather.uwyo.edu/upperair/sounding.html).
29

Table 1. Wind and weather observations for Sandoval Mesa, Colorado, (about 20 miles southwest of 

Pagosa Springs) reported by the University of Utah MesoWest site for March 22, 2009

(http://www.met.utah.edu/mesowest/). Speeds at or above the blowing dust thresholds, weather, and 

visibility (caused by or reduced by dust) have been highlighted in yellow.

Time in 

MST 

March 

22

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed 

in mph

Wind 

Gust in

mph

Wind 

Direction 

in 

Degrees Weather

Visibility 

in miles

23:53 34 54 6 32 235

22:53 34 50 12 30 299

21:53 39 30 11 45 268

20:53 45 15 15 44 243

19:53 48 14 16 37 226

18:53 51 14 13 43 223

17:53 53 14 19 41 219

16:53 57 14 17 42 211

15:53 58 15 19 37 203

14:53 58 16 16 28 205

13:53 57 20 9 25 192

12:53 57 20 12 20 189

11:53 56 27 7 22 184

10:53 51 34 10 19 189

9:53 46 44 10 17 181

8:53 41 45 8 14 181

7:53 42 43 9 13 182

6:53 41 40 8 13 185

5:53 42 38 5 16 211

4:53 44 37 5 17 226

3:53 45 34 8 20 211

2:53 45 32 8 21 232

1:53 46 30 9 20 207

0:53 48 28 9 19 211

 
30

Table 2. Wind and weather observations for Hayden, Colorado, (about 224 miles north of Pagosa 

Springs) reported by the University of Utah MesoWest site for March 22, 2009

(http://www.met.utah.edu/mesowest/). Speeds at or above the blowing dust thresholds, Weather, and

visibility (caused by or reduced by dust) have been highlighted in yellow.

Time in 

MDT 

(March 

22)

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed 

in 

mph

Wind 

Gust 

in 

mph

Wind 

Direction 

in 

Degrees Weather

Visibility 

in miles

23:55 34 86 6 60 overcast 10

22:55 34 86 9 310 overcast 6

21:55 34 86 17 25 270 overcast 5

20:55 41 56 15 25 250

mostly 

cloudy 10

19:55 46 42 7 250 overcast 10

18:55 52 26 22 29 290 overcast 10

17:55 55 21 14 25 230

mostly 

cloudy 10

16:55 55 16 25 47 210

mostly 

cloudy 10

15:55 63 14 36 43 230 clear 10

14:55 61 16 14 25 170

mostly 

clear 10

13:55 61 17 16 22 200 clear 10

12:55 61 18 21 31 220

partly 

cloudy 10

11:55 57 21 9 16 230 clear 10

10:55 55 24 18 24 240 clear 10

9:55 52 35 0 clear 10

8:55 46 53 8 30 clear 10

7:55 45 53 6 200

partly 

cloudy 10

6:55 43 61 12 130 overcast 10

5:55 43 61 13 110 clear 10

4:55 45 57 14 18 190

mostly 

clear 10

3:55 50 37 16 22 220 overcast 10

2:55 45 53 5 200 overcast 10

1:55 43 52 5 130 clear 10

0:55 46 46 8 120

mostly 

clear 10

0:15 45 49 10 120 clear 10
31

Table 3. Wind and weather observations for Alamosa, Colorado (about 64 miles east of Pagosa Springs) 

reported by the University of Utah MesoWest site for March 22, 2009

(http://www.met.utah.edu/mesowest/). Speeds at or above the blowing dust thresholds, Weather, and 

visibility (caused by or reduced by dust) have been highlighted in yellow.

Time 

in 

MST 

March 

22

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed in 

mph

Wind 

Gust in 

mph

Wind 

Direction 

in 

Degrees Weather

Visibility 

in miles

23:52 41 48 24 37 250

mostly 

cloudy 10

23:28 45 33 29 50 280 haze 6

23:16 45 31 36 50 260 haze 2.5

22:52 47 19 23 30 250 clear 10

21:52 50 17 23 30 260 clear 10

20:52 52 13 22 37 230 clear 10

19:52 53 23 16 27 200 clear 10

18:52 56 15 21 32 210 clear 10

17:52 60 11 27 40 200 clear 10

16:52 61 11 25 32 200 clear 10

15:52 62 11 30 37 220 clear 10

14:52 62 13 27 36 210 clear 10

13:52 62 13 21 30 220 clear 10

12:52 61 18 17 30 210 clear 10

11:52 58 22 21 29 230 clear 10

10:52 54 27 15 180 clear 10

9:52 52 28 14 180 clear 10

8:52 49 30 12 210 clear 10

7:52 45 34 13 200 clear 10

6:52 44 38 9 200 clear 10

5:52 47 37 10 180

mostly 

clear 10

4:52 50 32 29 36 240

mostly 

clear 10

3:52 45 36 9 210 clear 10

2:52 41 56 10 170 clear 10

1:52 45 51 10 200 clear 10

0:52 49 48 15 240

mostly 

cloudy 10
32

Table 4. Wind and weather observations for Durango, Colorado (about 42 miles west southwest of 

Pagosa Springs) reported by the University of Utah MesoWest site for March 22, 2009

(http://www.met.utah.edu/mesowest/). Speeds at or above the blowing dust thresholds, Weather, and 

visibility (caused by or reduced by dust) have been highlighted in yellow. 

Time 

in 

MST 

March 

22

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed 

in 

mph

Wind 

Gust 

in 

mph

Wind 

Direction 

in 

Degrees Weather

Visibility 

in miles

0:00 34 86 23 30 270

lt snow;

fog 1.5

23:53 35 85 15 250

lt snow; 

fog 6

23:49 36 80 16 250 lt snow 6

22:53 44 40 16 22 250 haze 5

22:28 43 45 8 18 270 haze 4

21:53 45 40 22 33 310 haze 3

21:46 45 39 23 39 310 haze 3

21:29 46 34 28 35 300 haze 2.5

21:19 48 29 18 27 300 haze 3

20:53 49 26 23 36 290 haze 5

19:53 56 12 22 43 240

mostly 

clear 8

18:53 59 12 25 39 210 clear 9

17:53 61 12 31 45 220 clear 9

16:53 64 11 29 51 210 clear 10

15:53 65 10 29 36 190 clear 10

14:53 63 13 22 28 180 clear 10

13:53 62 13 12 170

mostly 

clear 10

12:53 61 17 9 21 160 clear 10

11:53 60 17 12 20 220 clear 10

10:53 55 32 4 clear 10

9:53 52 35 0 clear 10

8:53 45 45 6 80 clear 10

7:53 41 53 7 70 clear 10

6:53 40 59 4 30 clear 10

5:53 42 55 4 30

mostly 

clear 10

4:53 45 47 0

mostly 

cloudy 10

3:53 44 51 4 10

partly 

cloudy 10

2:53 45 49 4 40 overcast 10

1:53 47 44 4 340 clear 10

0:53 48 42 4 360

mostly 

clear 10
33

Table 5. Wind and weather observations for Lamar, Colorado reported by the University of Utah 

MesoWest site for March 22, 2009 (http://www.met.utah.edu/mesowest/). Speeds at or above the blowing 

dust thresholds, weather, and visibility (caused by or reduced by dust) have been highlighted in yellow. 

Time in 

MST 

March 

22

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed 

in mph

Wind 

Gust in 

mph

Wind 

Direction 

in 

Degrees Weather

Visibility 

in miles

23:53 63 34 36 47 210 clear 10

22:53 63 29 32 43 200 clear 10

21:53 64 29 25 33 190 clear 10

20:53 67 25 29 37 200 clear 10

19:53 68 27 24 36 180 clear 10

18:53 73 22 27 37 180 clear 10

17:53 77 20 30 40 190 clear 10

16:53 81 8 17 22 230 clear 10

15:53 81 9 16 31 240 clear 10

14:53 78 10 20 250 clear 10

13:53 77 11 14 250 clear 10

12:53 76 14 10 230 clear 10

11:53 76 14 17 29 270 clear 10

10:53 68 27 16 240 clear 10

9:53 63 38 17 230 clear 10

8:53 61 44 17 230 clear 10

7:53 57 55 18 230 clear 10

6:53 54 64 17 220 clear 10

5:53 56 64 22 220 clear 10

4:53 57 64 25 36 210 clear 10

3:53 57 64 33 44 200 clear 10

2:53 59 62 32 47 200 clear 10

1:53 59 62 32 45 200 clear 10

0:53 60 53 25 32 190 clear 10
34

Table 6. Wind and weather observations for Farmington, New Mexico (about 76 miles southwest of 

Pagosa Springs) reported by the University of Utah MesoWest site for March 22, 2009

(http://www.met.utah.edu/mesowest/). Speeds at or above the blowing dust thresholds, Weather, and 

visibility (caused by or reduced by dust) have been highlighted in yellow. 

Time 

in 

MST 

March 

22

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed 

in 

mph

Wind 

Gust 

in 

mph

Wind 

Direction 

in 

Degrees Weather

Visibility 

in miles

23:53 33 96 20 27 290

lt snow; 

haze 1.25

23:42 34 93 15 300

lt snow; 

haze 2

23:29 36 93 22 31 290

lt rain; 

haze 6

23:22 37 87 23 33 290

lt rain; 

haze 10

22:53 41 67 23 35 290 haze 10

22:11 46 46 22 31 280 haze 10

21:53 46 47 20 32 290 haze 6

20:53 50 34 21 30 300 haze 6

20:33 52 30 27 38 310 haze 6

20:15 54 26 27 44 290 haze 5

19:53 60 10 35 54 230 overcast 3

19:37 61 11 40 51 240 haze 4

19:30 61 11 25 40 250 haze 2.5

19:06 63 9 36 55 230 haze 1

18:53 64 10 37 51 230 haze 2.5

18:29 64 10 37 47 230 haze 2.5

18:11 66 10 30 50 220 haze 2.5

17:53 68 10 31 46 220 haze 4

16:53 70 10 27 38 210 clear 8

15:53 71 10 31 40 210 clear 10

14:53 71 8 27 36 200 clear 10

13:53 71 8 20 30 220 clear 10

12:53 68 12 16 35 220 clear 10

11:53 65 14 8 150 clear 10

10:53 62 22 6 clear 10

9:53 57 30 4 clear 10

8:53 51 41 7 10 clear 10

7:53 51 39 4 110 clear 10

6:53 56 31 12 230 clear 10

5:53 57 31 12 240 clear 10

4:53 56 29 0 clear 10

3:53 55 30 5 90 clear 10

2:53 57 25 4 260 clear 10

1:53 58 26 5 210

mostly 

clear 10

0:53 61 21 14 220 clear 10
35

Table 7. Wind and weather observations for Gallup, New Mexico (about 156 miles southwest of Pagosa 

Springs) reported by the University of Utah MesoWest site for March 22, 2009 

(http://www.met.utah.edu/mesowest/). Speeds at or above the blowing dust thresholds, Weather, and 

visibility (caused by or reduced by dust) have been highlighted in yellow. 

Time 

in 

MST 

March 

22

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed 

in 

mph

Wind 

Gust 

in 

mph

Wind 

Direction 

in 

Degrees Weather

Visibility 

in miles

23:53 35 72 21 31 300 lt snow 10

22:53 45 30 31 48 250 clear 10

21:53 49 23 29 47 250

mostly 

cloudy 10

20:53 53 22 33 48 230

mostly 

cloudy 10

19:53 54 18 29 45 240

mostly 

clear 10

18:53 57 14 32 50 230 clear 10

17:53 62 12 36 50 220 clear 10

16:53 65 11 28 48 220 clear 10

15:53 66 10 36 50 210 clear 10

14:53 65 11 28 40 230 clear 10

13:53 64 15 29 38 210 clear 10

12:53 63 15 23 36 220 clear 10

11:53 60 18 25 31 240 clear 10

10:53 58 22 18 25 220 clear 10

9:53 53 28 17 28 220 clear 10

8:53 50 36 16 21 210 clear 10

7:53 47 42 10 200 clear 10

6:53 46 47 7 200 clear 10

5:53 46 47 8 210 clear 10

4:53 49 42 8 220 clear 10

3:53 49 41 12 230 clear 10

2:53 48 42 9 210 clear 10

1:53 47 40 8 190

mostly 

clear 10

0:53 49 36 6 210 clear 10
36

Table 8. Wind and weather observations for Kykotsmovi Village, Arizona (about 225 miles southwest of 

Pagosa Springs) reported by the University of Utah MesoWest site) for March 22, 2009

(http://www.met.utah.edu/mesowest/. Speeds at or above the blowing dust thresholds, Weather, and 

visibility (caused by or reduced by dust) have been highlighted in yellow. 

Time in 

MST 

March 

22

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed 

in mph

Wind 

Gust in 

mph

Wind 

Direction 

in 

Degrees Weather

Visibility 

in miles

23:13 31 73 15 24 269

22:13 34 72 19 29 273

21:13 34 92 17 38 277

20:13 33 85 25 40 302

19:13 43 55 28 47 296

18:13 54 21 34 50 224

17:13 56 17 39 54 225

16:13 60 14 38 61 236

15:13 61 11 42 60 232

14:13 64 12 40 56 219

13:13 64 11 39 55 225

12:13 65 12 33 46 214

11:13 63 13 27 40 219

10:13 60 17 18 31 209

9:13 58 23 19 28 192

8:13 53 39 13 18 191

7:13 33 71 4 8 47

6:13 33 62 5 6 43

5:13 38 59 5 6 37

4:13 40 51 1 5 18

3:13 44 47 1 7 115

2:13 49 41 6 10 216

1:13 49 38 6 15 271

0:13 54 35 10 15 208
37

Table 9. Wind and weather observations for Window Rock, Arizona (about 160 miles southwest of 

Pagosa Springs) reported by the University of Utah MesoWest site for March 22, 2009

(http://www.met.utah.edu/mesowest/). Speeds at or above the blowing dust thresholds, Weather, and 

visibility (caused by or reduced by dust) have been highlighted in yellow

Time 

in 

MST 

March 

22

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed 

in 

mph

Wind 

Gust 

in 

mph

Wind

Direction 

in 

Degrees Weather

Visibility 

in miles

23:58 30 86 15 21 280 lt snow 3

23:53 30 88 10 18 280

lt snow; 

fog 2.5

23:50 30 86 9 18 280

lt snow; 

fog 2

23:43 30 86 13 280

lt snow; 

fog 1

23:18 32 86 23 29 300

lt snow; 

fog 1.75

23:10 36 80 15 270 lt snow 5

22:53 37 72 17 29 270

unknown 

prcp 10

22:32 39 65 20 30 290

mostly 

cloudy 10

21:53 45 27 33 55 230 clear 10

20:53 48 21 31 45 250

mostly 

cloudy 7

19:53 51 20 24 40 230

mostly 

cloudy 8

18:53 54 15 33 53 230 clear 10

17:53 58 14 28 47 220 clear 10

16:53 61 13 31 50 210 clear 9

15:53 62 12 36 50 210 clear 10

14:53 64 13 28 41 200 clear 10

13:53 62 14 24 37 210 clear 10

12:53 60 17 22 36 220 clear 10

11:53 58 18 21 35 230 clear 10

10:53 55 22 16 27 220 clear 10

9:53 51 32 13 18 190 clear 10

8:53 46 42 9 17 170 clear 10

7:53 43 49 6 110 clear 10

6:53 44 49 6 170 clear 10

5:53 45 45 4 180 clear 10

4:53 45 47 6 180 clear 10

3:53 46 43 7 180 clear 10

2:53 46 42 5 180 clear 10

1:53 45 42 0

mostly 

clear 10

0:53 48 35 4 180

mostly 

clear 10
38

Table 10. Wind and weather observations for Winslow, Arizona (about 260 miles southwest of Pagosa 

Springs) reported by the University of Utah MesoWest site for March 22, 2009

(http://www.met.utah.edu/mesowest/). Speeds at or above the blowing dust thresholds, Weather, and 

visibility (caused by or reduced by dust) have been highlighted in yellow. 

Time 

in 

MST 

March 

22

Temperature 

Degrees F

Relative 

Humidity 

in %

Wind 

Speed 

in 

mph

Wind 

Gust 

in 

mph

Wind 

Direction 

in 

Degrees Weather

Visibility 

in miles

23:56 41 36 16 270 overcast 10

22:56 39 55 15 310 overcast 10

21:56 38 73 18 29 330 overcast 10

21:18 43 61 14 27 330 overcast 10

20:56 51 32 28 45 240 overcast 10

19:56 52 28 24 35 230 clear 10

18:56 55 18 31 51 220 clear 10

17:56 59 14 38 56 210 clear 8

16:56 64 12 38 59 200 clear 10

15:56 66 10 48 62 200 haze 4

14:56 68 13 44 58 190 clear 10

13:56 69 11 44 58 200 clear 10

12:56 70 12 36 51 200 clear 10

11:56 69 12 38 51 210 clear 8

10:56 68 13 32 41 210 clear 10

9:56 66 14 25 33 190

8:56 61 18 14 21 180 clear 10

7:56 50 32 8 140 clear 10

6:56 42 44 6 90 clear 10

5:56 45 42 7 130 clear 10

4:56 47 40 8 90 clear 10

3:56 46 43 6 130 clear 10

2:56 44 49 6 90 clear 10

1:56 45 45 5 110 clear 10

0:56 49 39 5 140 clear 10
39

Figure 24. Wind directions and gust speeds caused by low-level jet over the Great Plains at 7:47Z March 

22, 2009 or 12:47 AM MST on March 22, 2009 (http://www.met.utah.edu/mesowest/).

Figure 25. Friction velocities in meters/second from the NOAA NCEP North American Model with 12 

kilometer grid spacing at 6Z March 22, 2009 (11 PM MST March 21). 
40

Figure 26. Friction velocities in meters/second from the NOAA NCEP North American Model with 12 

kilometer grid spacing at 12Z March 22, 2009 (5 AM MST March 22). 

Figure 27. Friction velocities in meters/second from the NOAA NCEP North American Model with 12 

kilometer grid spacing at 18Z March 22, 2009 (11 AM MST March 22). 
41

Figure 28. Friction velocities in meters/second from the NOAA NCEP North American Model with 12 

kilometer grid spacing at 0Z March 23, 2009 (5 PM MST March 22). 

Wind Advisories issued by the NWS Forecast offices in Grand Junction, Colorado; Flagstaff, Arizona; 

and Albuquerque, New Mexico, for western Colorado, eastern Utah, northeast Arizona, and northwest 

New Mexico are presented in Attachment D. They show that strong winds and areas of blowing dust 

were expected to occur on March 22, 2009, throughout much of northeast Arizona, northwest New 

Mexico, western Utah, and western Colorado.

The Center for Snow and Avalanche Studies (http://www.snowstudies.org/index.html) has been studying 

the effects of desert dust deposition on snowpack albedo and snowmelt in the San Juan Mountains of 

Colorado. Figure 29 contains the center‘s log of events that deposited dust on the snowpack of the San 

Juan Mountains. It lists March 22, 2009, as one of twelve Dust-on-Snow events for the 2008/2009 water 

year. 

Figure 30 shows a MODIS true color satellite image centered on Arizona on March 22, 2009, at 21:18Z 

(2:18 PMMST March 22) (from the United States Forest Service site at 

http://activefiremaps.fs.fed.us/imagery.php?op=fire&fireID=az-000). It shows a large, dense area of 

blowing dust over northeast Arizona and the Four Corners area including the Painted Desert and Little 

Colorado River Valley region. The area of blowing dust includes plumes of dust oriented along southwest 

to northeast lines consistent with the transport flow described in other products presented in this report. 

The area of blowing dust in the MODIS satellite picture in Figure 30 is in the middle of the matrix used 

for the forward trajectories in Figures 19 through 22.

Figure 31 contains the Descriptive Text Narrative for Smoke/Dust Observed in Satellite Imagery from 

NOAA‘s Satellite Services Division through 0045Z March 23 (Smoke Text Product - Satellite Services 

Division). It describes blowing dust moving from Arizona into southwest Colorado. Kykotsmovi Village 

is in the middle of the area of blowing dust in the MODIS satellite picture in Figure 30. The observations 
42

in Table 8 from Kykotsmovi Village have ten hours of wind speeds at or above blowing dust thresholds of 

25 mph and or wind gusts of 40 mph. Table 10 has the observations for Winslow, Arizona, which is on 

the south side of the area where dust is being lifted into the atmosphere. It has eleven hours of wind 

speeds at or above the blowing dust thresholds of 25 and or wind gusts of 40. The National Weather 

Service observations from Durango, Colorado, and Farmington, New Mexico, in Tables 4 and 6 both have 

six hours of observations with visibilities reduced due to haze. This haze is caused by the dust being 

transported from northeast Arizona and northwest New Mexico. Note both stations have additional hours 

of reduced visibility after the frontal passage due to increased relative humidity levels. 

Figure 32 shows the output for dust from the NAAPS (Navy Aerosol Analysis and Prediction 

System) Global Aerosol Model for March 22, 2009 (http://www.nrlmry.navy.mil/aerosol/). It 

shows a large area of blowing dust over northern Arizona moving over much of Colorado by 11 

PM on March 22, 2009. The NAAPS model output is based on soil moisture content, soil 

erodibility factors, and modeled meteorological factors conducive to blowing dust (for a 

description of NAAPS see: http://www.nrlmry.navy.mil/aerosol_web/Docs/globaer_model.html). 

Although the NAAPS forecast products can over predict dust PM10, they do provide an 

independent calculation of the potential for blowing dust and the spatial extent of blowing dust 

for this event. The highest NAAPS concentrations of dust PM10 are in northeastern Arizona. All 

of the products discussed in this report point to a widespread, regional-scale dust storm that 

originated in portions of Arizona and grew to cover most of Colorado. 
43

Figure 29. Dust-on-Snow Deposition Events Log at the Senator Beck Basin Study Area on Red Mountain 

Pass, Colorado. (The Center for Snow and Avalanche Studies, http://www.snowstudies.org/index.html)

Colorado Dust-on-Snow (CODOS)

Dust-on-Snow Deposition Events Log

Thanks to our original National Science Foundation research grants for collaborative research 

(grants ATM-0432327 to Painter at National Snow and Ice Data Center and ATM-0431955 to Landry 

at Center for Snow and Avalanche Studies), and to the subsequent support of the emergent Colorado 

Dust-on-Snow program by Colorado water districts, this program has accumulated several seasons of 

dust-on-snow observations at our Senator Beck Basin Study Area (SBBSA) at Red Mountain Pass, 

summarized in the table below. It is reasonable to assume that our skill at detecting dust-on-snow 

events has improved and that we may have failed to observe very small events during the early years 

of this work. Therefore the table represents an absence of events in grey for the first two years of 

observation but thereafter indicates an absence of observed events as ―0‖ (zero).

Dust-on-Snow Events Documented per Month, by Winter

Senator Beck Basin Study Area at Red Mountain Pass – San Juan Mountains

Oct Nov Dec Jan Feb Mar Apr May Jun Total

2002/2003 2 1 3

2003/2004 2 1 3

2004/2005 0 0 0 0 0 1 2 1 0 4

2005/2006 0 0 1 0 1 1 3 2 0 8

2006/2007 0 0 1 0 1 1 3 1 1 8

2007/2008 0 0 0 0 0 3 3 1 0 7

2008/2009 1 0 1 0 1 4 5 0 0 12

Dates of the events, by winter/spring season, were as follows (WY = Water Year):

2002/2003 (WY2003): Feb 3, Feb 22, Apr 2-3

2003/2004 (WY 2004): Apr 17, Apr 28, May 11

2004/2005 (WY 2005): Mar 23, Apr 4, Apr 8, May 9

2005/2006 (WY 2006): Dec 23, Feb 15, Mar 26, Apr 5, Apr 15, Apr 17, May 22, May 27

2006/2007 (WY 2007): Dec 17, Feb 27, Mar 27, Apr 15, Apr 18, Apr 24, May 4, Jun 6

2007/2008 (WY 2008): Mar 16, Mar 26-27, Mar 30-31, Apr 15, Apr 21, Apr 30, May 12

2008/2009 (WY 2009): Oct 11, Dec 13, Feb 27, Mar 6, Mar 9, Mar 22, Mar 29, Apr 3, Apr 8, Apr 

15, Apr 24, Apr 25
44

Figure 30. MODIS satellite image centered on Arizona at 21:18Z March 22, 2009 (2:18 PM MST March 

22, 2009, http://activefiremaps.fs.fed.us/imagery.php) showing widespread blowing dust over the Painted 

Desert and Little Colorado River Valley region of the state.
45

Figure 31. Smoke Text Product Satellite Services Division, Descriptive Text Narrative for Smoke/Dust 

observed in satellite imagery through 0045Z March 22, 2009 (Smoke Text Product - Satellite Services 

Division).

SUNDAY MARCH 22, 2009

DESCRIPTIVE TEXT NARRATIVE FOR SMOKE/DUST OBSERVED IN SATELLITE IMAGERY 

THROUGH 0045Z MARCH 23, 2009

California:

In San Bernardino and Inyo counties, blowing dust is moving rapidly to

the east into far southern Nevada.

Arizona:

In Navajo and Apache counties, blowing dust is moving quite fast into

northwest New Mexico, far southeastern Utah, and southwest Colorado.

In Louisiana and Mississippi, a couple dense smoke plumes were observed

moving to the north and west.

THE FORMAT OF THIS TEXT PRODUCT IS BEING MODIFIED. IT WILL NO LONGER

DESCRIBE THE VARIOUS PLUMES THAT ARE ASSOCIATED WITH ACTIVE FIRES. THESE

PLUMES ARE DEPICTED IN VARIOUS GRAPHIC FORMATS ON OUR WEB SITE:

JPEG: http://www.ssd.noaa.gov/PS/FIRE/hms.html

GIS: http://www.firedetect.noaa.gov/viewer.htm

KML: http://www.ssd.noaa.gov/PS/FIRE/kml.html

THIS TEXT PRODUCT WILL CONTINUE TO DESCRIBE SIGNIFICANT AREAS OF SMOKE

WHICH HAVE BECOME DETACHED FROM AND DRIFTED SOME DISTANCE AWAY FROM THE

SOURCE FIRE, TYPICALLY OVER THE COURSE OF ONE OR MORE DAYS. IT WILL ALSO

STILL INCLUDE DESCRIPTIONS OF BLOWING DUST.

ANY QUESTIONS OR COMMENTS REGARDING THESE CHANGES OR THE SMOKE TEXT

PRODUCT IN GENERAL SHOULD BE SENT TO SSDFireTeam@noaa.gov
46

. 

Figure 32. NAAPS forecasted dust concentrations for March 22, 2009 (source:

http://www.nrlmry.navy.mil/flambe-bin/aerosol/display_directory_aer2?DIR=/web/aerosol/public_html/globaer/ops_01/wus/).
47

3.0 Ambient Monitoring Data and Statistics

A PM10 concentration that exceeded the level of the twenty-four-hour NAAQS was monitored in Pagosa 

Springs, Colorado on Sunday March 22, 2009. An exceedance of 255 μg/m3 was recorded at the Pagosa 

Springs Middle School monitoring site. This exceedance was caused by a nature; a regional dust storm 

that was not preventable or reasonably controllable. The spatial extent of this dust storm was from the 

deserts of northeastern Arizona and northwestern New Mexico through the southern and central portions 

of Colorado (see section 2). This weather system adversely affected the air quality in Pagosa Springs and 

had a negative impact on PM10 concentrations at several other monitoring stations in Colorado, including 

Mount Crested Butte, Lamar and even a small impact on Steamboat Springs. Unfortunately, this was not 

a once every three-day sampling day; thus, the high PM10 was only captured by the daily monitoring sites, 

which make up less than one third of the PM10 network. See figure 1 in section 2, (PM10 High event in 

Colorado) for a map of all the valid PM10 concentrations recorded in Colorado on March 22, 2009. The 

255 μg/m3at Pagosa Springs was the only site greater than the NAAQS of 150 μg/m3. 

Monitored PM10 levels before and after the March 22, 2009 episode were low as can be seen in Table 1

and Figure 33. The APCD reviewed PM10 monitoring data in Pagosa Springs and the surrounding areas 

in the path of the dust storm (see section 3.1). The PM10 concentrations in Pagosa Springs on March 22, 

2009 were compared to the concentrations on the days before and the days after the regional dust storm. 

Figure 33 clearly shows that the regional blowing dust storm adversely affected the air quality in Pagosa 

Springs. The days before and after the event were quite low with concentrations that are typical for 

winter in Pagosa Springs (see Table 11 and section 3.1, the Historical Fluctuations of PM10

Concentrations in Pagosa Springs). Other PM10 monitoring sites in Colorado had elevated PM10

concentrations that were above their typical seasonal and historical concentrations on March 22, 2009 as 

explained in section 3.1 below, but these sites did not exceed the 24-hour NAAQS. All other Colorado 

sites recorded concentrations between 30 μg/m3in Denver, which usually has low concentrations during 

these southwestern regional dust storm events, and 111 μg/m3in Lamar on March 22, 2009. Also, the 

Alamosa Municipal Building site sample was invalid and the sample from the Alamosa Adams State 

College site was not significantly elevated. This is perfectly plausible as dust storms often have uneven 

concentrations and impact site differently even when they are geographically close to each other. For 

example, the two Lamar sites in Table 11 below are only separated by one mile of flat terrain, but their 

PM10 concentrations on March 22, 2009 are significantly different (111 μg/m3and 48 μg/m3). PM10

concentrations are known to be highly localized. 

Table 11. Pagosa Springs PM10 Concentrations Before and After March 22, 2009 Regional Dust Storm. 

Date Pagosa Springs Mount Crested 

Butte

Lamar Power 

Plant

Lamar Municipal

03/19/2009 39 μg/m340 μg/m343 μg/m323 μg/m3

03/20/2009 31 μg/m342 μg/m344 μg/m335 μg/m3

03/21/2009 29 μg/m333 μg/m373 μg/m325μg/m3

03/22/2009 255 μg/m3

93 μg/m3111 μg/m348 μg/m3

03/23/2009 68 μg/m316 μg/m3

90 μg/m398μg/m3

03/24/2009 16 μg/m314 μg/m371 μg/m370 μg/m3

03/25/2009 24 μg/m315 μg/m340 μg/m330 μg/m3

The March 22, 2009 regional dust storm had a large spatial extent covering most of northeast Arizona, 

northwest New Mexico, and it moved into southern and central Colorado and was captured at the daily 

PM10 sites from Pagosa Springs to Mount Crested Butte to Lamar. Since only daily PM10 sites were 

operating on March 22, 2009 it is not possible to see many high PM10 concentrations across the state. For 
48

example, Durango and Telluride were in the path of the dust storm but were not monitoring on March 22, 

2009. When the dust storm reached into Lamar located in southeast Colorado it was later in the evening 

and crossed over midnight into the early hours of the next day, March 23, 2009. That is why PM10

concentrations were still elevated in Lamar on March 23, 2009. There are also many weather stations 

across the path of the dust storm that recorded high winds and haze, which is blowing dust when there is 

no precipitation present. Most of these weather stations are located in areas that do not have PM10

monitoring sites. These meteorological stations can act as surrogates and help demonstrate the extent of 

the blowing dust in towns where there are no daily PM10 monitoring sites. See section 2 for the full 

meteorological details and extent of the regional dust storm. 

Other data that shows the extent of the regional dust storm includes the Colorado Dust-on-Snow 

(CODOS) stations and news accounts and e-mails from credible eye witnesses. These sites record the 

date and other data when dust reached the high altitude monitoring stations (see Section 2 for details). 

March 22, 2009 was a dust on snow event according to the CODOS records 

(http://www.snowstudies.org/CODOS/CSAS%20Dust-on-Snow%20Log.pdf). The APCD also received

e-mails and pictures from credible eye witnesses in Aspen and Mount Crested Butte concerning a large 

dust storm that turned in to a dirty snow storm. These are shown in section 4.0 News Accounts and 

Credible Evidence. The town manager of Mt. Crested Butte, Joe Fitzpatrick, e-mailed Ray Mohr at the 

APCD that, ―On March 22 and March 23, 2009 Mt. Crested Butte and Gunnison County experienced a 

major wind event with the front edge of this snow storm that blew a large amount of the red dust in from 

the desert. So we had red dust ahead of and mixed with our snow last Monday morning.‖ And, Lee 

Cassin, the director of the Aspen/Pitkin Environmental Health Department, sent pictures of the dust on 

vehicles and an e-mail describing the event, ―last night (March 22) we had a very unusual weather event, 

and our office has been getting calls from citizens and the media. We had winds the last couple of days 

(Sat. and Sun.), though not extremely strong. Last night around 8 or so, it started raining and then 

snowing, or rain mixed with snow. The next morning there was "brown snow" everywhere. It looked like 

snowplows had coated everything with brown road slush and sand. After the initial event, there was 

normal snow, but the first frozen rain/snow was completely brown...‖ 

The time series graph in figure 33 shows the seasonal PM10 concentrations at the Pagosa Springs site 

during the months of March and April, 2009. The graph shows five regional blowing dust events that 

occurred that spring and impacted the town of Pagosa Springs. The PM10 concentrations on the days 

before and after the 22 March blowing dust event were quite low and this chart shows that event to be 

concentrated on that single day in Pagosa Springs. The other blowing dust events in March and April 

showed similar results; low PM10 concentrations before and after the blowing dust days. The town of 

Pagosa Springs at 7,103 ft. (2165 m) is located in a mountain valley topographic setting surrounded by 

mostly coniferous forests. There are very few anthropogenic local sources of geologic PM10 sized dust in 

the area as most of the area is covered in vegetation. Also, the anthropogenic sources are well controlled 

due to a State Implementation Plan (SIP) / PM10 Maintenance Plan. See section 5.0 Local Dust Controls 

for a comprehensive list of PM10 control measures employed in Pagosa Springs through the PM10 SIP / 

Maintenance Plan. 

There is one blowing dust event in the Pagosa Springs time series charts below that needs further 

explanation. On April 8, 2009 there was a regional blowing dust event that impacted other areas of 

Colorado including the Alamosa Municipal Building site (157 μg/m3) Alamosa Adams State College (135 

μg/m3), Breckenridge (101 μg/m3), Steamboat Springs (78 μg/m3), and Mount Crested Butte (56 μg/m3). 

However, Pagosa Springs recorded a concentration of only 31 μg/m3on April 8, 2009. Also, on April 6, 

2009 Pagosa Springs recorded a concentration of 182 μg/m3, while all other sites in Colorado only 

recorded concentrations between 13 μg/m3at Alamosa Adams State College to 40 μg/m3at the Denver 

Visitor‘s Center site. After a thorough investigation and finding no meteorological reason for the 
49

discrepancy, the Division believes the site operator failed to follow proper procedures and wrote the 

wrong dates on the chain of custody forms. 

Figure 33. PM10 Seasonal Concentrations in Pagosa Springs March and April, 2009.

From the limited PM10 data (daily sites only) on March 22, 2009 in Pagosa Springs, Mount Crested Butte, 

Lamar, and Steamboat Springs before and after the high wind blowing dust event clearly shows that 

March 22, 2009 was a high PM10 event. Furthermore, the regional blowing dust event on that day caused 

a PM10 concentration that was much higher than normal for the two month (March and April) seasonal 

spring period of interest. Even though the PM10 data for Pagosa Springs during the months of March and 

April shows three additional PM10 exceedances, these were also caused by large naturally occurring 

regional blowing dust events that were not preventable or reasonably controllable. The March and April, 

2009 period was exceptional in that it contains one of the most frequent regional blowing dust periods in 

the history of PM10 monitoring in Colorado and was well documented by numerous sources. There were 

six regional blowing dust events in the two month period that covered large spatial areas of Colorado, 

Arizona and New Mexico and most of these will be documented in future exceptional event technical 

support documents by the APCD. 

Steamboat Springs is different from most of the impacted sites as it is located farther away from the 

source area and in a relatively unique area of Colorado. Steamboat has the only state operated PM10

monitoring station located in the northwestern area of the state and in the northern mountain region. 

Steamboat Springs is located 222 miles (357.4 km) north of Pagosa Springs with very complex terrain 

(13,000 – 14,000 foot peaks) and several mountain ranges between the two towns. Steamboat Springs is 

a ski area town and the PM10 monitor is located at an elevation of 6,739 feet (2,054 m). Being that far 

north Steamboat is not usually impacted by the dust storms generated in the Four Corners region as they 

usually travel from the southwest to the northeast and east. Steamboat Springs is in a regime of its own. 

75

255

100

225

182 188

0

50

100

150

200

250

300

Concentration ug/m3

Pagosa Springs PM10 March & April, 2009

Pagosa Springs

March 22, 2009 Regional Blowing Dust Event

April 3, 2009 Regional Blowing Dust Event

April 25, 2009 

Regional Blowing 

Dust Event

Suspected operator 

date error should 

be 4/8/09 Regional 

Blowing Dust Event

March 22, 2009 Regional Blowing Dust Event

April 3, 2009 Regional Blowing Dust Event

April 25, 2009 

Regional Blowing 

Dust Event March 29, 2009 

Regional Blowing Dust 

Event

Suspected operator 

date error should 

be 4/8/09 Regional 

March 5, 2009 Blowing Dust Event

Regional Blowing Dust 

Event
50

Steamboat is also impacted by daily temperature inversions and stagnant air due to its mountain-valley 

topography and the town is located in a valley bottom setting on the western side of the Gore Range 

Mountains. The Gore Range blocks the typical westerly flow of air. Steamboat Springs has a PM10 SIP 

Maintenance Plan that has required controls of geologic dust from the roads, such as using clean sand, 

sweeping highway 40, the main thoroughfare, immediately after sanding events. The Steamboat Springs 

SIP also has local restrictions on woodburning devices. (Reference: Steamboat Springs PM10

Redesignation Request and Maintenance Plan – Adopted by the Colorado Air Quality Control 

Commission November 15, 2001.) These control measures have kept the PM10 concentrations well below 

the 24-hour NAAQS of 150 μg/m3. The remote northern location as well as the SIP control measures 

used in Steamboat Springs explains why the PM10 concentration in Steamboat were only moderately 

elevated on March 22, 2009. 

The elevated PM10 concentrations in Mount Crested Butte (93 μg/m3), Lamar (109 μg/m3and 49 μg/m3, 

Power Plant and Municipal Building sites, respectively), and in Steamboat Springs (54 μg/m3) on March 

22, 2009 and the continuing high PM10 concentrations on March 23, 2009 in Lamar (90 μg/m3and 98 

μg/m3, Power Plant and Municipal Building sites, respectively) provide additional direct evidence that the 

regional dust storm brought dust to other areas in Colorado. There were probably no other PM10

exceedances recorded because the PM10 daily network is sparse in this area of Colorado and dust storms 

do not have homogeneous deposition. A more robust network of PM10 monitors on a daily frequency 

would likely have shown more exceedances or elevated concentrations from this natural blowing dust 

event. Section 2 provides the meteorological evidence for the spatial extent of this regional blowing dust 

event including the dust on snow data from the Colorado Dust-on-Snow (CODOS) network. 

Figure 34 shows the annual PM10 data for 2009. There were at least six regional blowing dust events 

identified by the Division that adversely affected the air quality in Pagosa Springs in 2009. Also, the data 

indicates that PM10 is well controlled in Pagosa Springs. If it were not, there should be high PM10 spikes 

during the winter when temperature inversions are strongest, which is common in Colorado mountain 

valley regimes. Instead, high PM10 concentrations are only seen when winds are highest during regional 

dust storm events. All of these six dust storms originated in the Four Corners area from deserts in 

northeast Arizona and northwest New Mexico. 
51

Figure 34. PM10 Annual Concentrations in Pagosa Springs during 2009.

Figure 35 shows a time series graph for multiple years of PM10 data that was created for Pagosa Springs 

to show how PM10 varies seasonally and from year to year. EPA Guidance states that a 3 – 5 year timesseries graph for the exceptional event should be provided to show seasonal distribution of PM10

concentrations. APCD selected the five (5) full years of data preceding the event and a little more by 

including the first calendar quarter (Jan. – March, 2009) in which the event occurred. Data after the event 

are not shown as the documentation of exceptional events has not yet occurred. 

75

255

100

225

182 188

0

50

100

150

200

250

300

Concentration ug/m3

Pagosa Springs PM10 2009

Pagosa Springs

Suspected operator date error should be 

4/8/09 Regional Blowing Dust Event

March 22, 2009 Regional Blowing Dust Event

April 3, 2009 Regional Blowing Dust Event

April 25, 2009 Regional Blowing Dust Event

March 29, 2009 

Regional Blowing 

Dust Event

March 5, 

2009 

Eastern 

Colo. Reg. 
52

Figure 35. Five Year Time-Series Graph of PM10 in Pagosa Springs

The time-series graph above shows that PM10 in Pagosa Springs sometimes has high concentrations in the 

winter to early summer period (Jan. to June). Statistically, however, there is little seasonal variation or 

month-to-month variation as discussed below in section 3.1 ―Historical Fluctuations of PM10 

Concentrations Pagosa Springs.‖ Most of the concentrations above are below 50 ug/m3and there are just 

four excursions above 100 ug/m3. The PM10 exceedance on March 22, 2009 is the only exceedance in the

five year period. A near-exceedance of 149 ug/m3occurred on May 1, 2008, but that date was not 

documented as an exceptional event by the Division as it was not an exceedance of the 24-hour PM10

NAAQS. However, there is a high probability that the 149 ug/m3 was an exceptional event due to high 

winds and blowing dust. There is ample weather data to demonstrate that May 1, 2008 had sustained 

wind speeds above the blowing dust threshold of greater than 25 mph (see 

http://mesowest.utah.edu/index.html). The other two concentrations greater than 100 ug/m3(122 ug/m3on 

February 15, 2006 and 102 ug/m3on June 6, 2007) were also associated with high regional sustained 

winds above the blowing dust threshold of 25 mph and gusts of much higher winds also occurred on the 

high wind days. Both of these dates are recorded in the Colorado Dust-on-Snow Deposition Events Log 

(see Table 13 in section 2.0 above) as regional blowing dust events that brought windblown dust to snow 

covered areas near high mountain passes in Colorado, where there are little or no local anthropogenic 

sources of PM10. Furthermore, the February 15, 2006 event was a documented exceptional event that 

caused an exceedance in Alamosa and Grand Junction, which are east and north of Pagosa Springs, 

respectively (see exceptional event Technical Support Documentation for Alamosa on 2/15/06.) 

The following three time series charts in Figures 36 though 38 show the seasonal March and April 2009 

PM10 data Mount Crested Butte, Lamar, and Steamboat Springs, respectively. These charts present 

additional evidence that that the regional dust storm brought elevated PM10 concentrations to other areas 

of Colorado on March 22, 2009. The Pagosa Springs, Mount Crested Butte, and the Lamar annual data 

122

102

149

255

0

50

100

150

200

250

300

01/01/04 01/01/05 01/01/06 01/01/07 01/01/08 01/01/09

Concentration ug/m3

Pagosa Springs PM10 2004 - 2011

Pagosa Springs

Site down for 

re-roofing

Regional High Wind Blowing Dust Events
53

charts clearly show that the regional blowing dust storm adversely affected the air quality in those towns. 

This is not as evident in the Steamboat Springs annual data chart. But, the main reason for the difference 

is the distant location and direction from the source area as discussed above. 

Mount Crested Butte is located 112 miles (182 km) north of Pagosa Springs with very complex terrain 

(13,000 – 14,000 foot peaks) between the two towns. Mount Crested Butte is a ski area town and the 

PM10 monitor is located at an elevation of 9,403 feet (2,866 m). 

CDPHE has a Memorandum of Agreement (MOA) in Mount Crested Butte to control dust from roads and 

other anthropogenic sources in the town. Furthermore, the Mount Crested Butte area was snow covered 

on March 22, 2009. The major sources of PM10 in Crested Butte: re-entrained dust from local streets 

(there are no major streets or highways in town) and residential wood burning. The largest contributor is 

re-entrained dust and the street dust was likely well controlled due to the controls in the MOA (using 

more durable sand and magnesium chloride to reduce dust on parking lots, more frequent street sweeping, 

and a construction ordinance to reduce mud and dirt carry-out on streets). (Reference: Mount Crested 

Butte, Memorandum of Agreement, Effective March 5, 1998.) 

Figure 36. PM10 Seasonal Concentrations in Mount Crested Butte, March and April, 2009.

93

81 80

56

0

50

100

150

200

250

300

Concentration ug/m3

Mt. Crested Butte PM10 Data March & April 2009

Mt. Crested Butte

April 3, 2009 Regional Blowing Dust 

Event

March 22, 2009 Regional Blowing 

Dust Event

March 29, 2009 Regional Blowing 

Dust Event

April 8, 2009 Regional Blowing 

Dust Event
54

Figure 37. PM10 Seasonal Concentrations in Lamar, March and April, 2009.

111

171

176

48

98

55

0

50

100

150

200

250

300

Concentration ug/m3

Lamar PM10 Data March & April 2009

Lamar - Power Plant Lamar - Municipal Bldg.

March 22 & 23, 2009 

Regional Blowing 

Dust Event

March 5, 2009 Eastern Colorado 

Regional Blowing Dust Event

9

0

138

March 26, 2009 Possible Dust Storm

Event Preceding Snow 
55

Figure 38. PM10 Seasonal Concentrations in Steamboat Springs, March and April, 2009.

Figures 39 through 41 show all PM10 data for 2009 in Mount Crested Butte, Lamar, and Steamboat 

Springs, respectively. This data confirms that without a regional blowing dust event PM10 levels do not 

typically exceed 50 μg/m3at the mountain locations and about 60 μg/m3in Lamar. This presents an even 

more dramatic picture of typical PM10 concentrations in the three areas that are spread far apart and in 

different topographical regions. 

83 78

62 54

57

0

50

100

150

200

250

Concentration ug/m

3

Steamboat Springs PM10 Data March & April 

2009 

Steamboat Springs 

March 22, 2009 Regional Blowing Dust Event

March 5, 2009 Eastern Colorado Regional Blowing Dust Event

April 8, 2009 Regional 

Blowing Dust Event
56

Figure 39. PM10 Annual Concentrations in Mount Crested Butte during 2009.

93

81 80

56

0

50

100

150

200

250

300

Concentration ug/m3

Mt. Crested Butte PM10 2009

Mt. Crested Butte

March 22, 2009 Regional Blowing Dust Event

March 29, 2009 Regional Blowing Dust Event

April 3, 2009 Regional Blowing Dust Event

April 8, 2009 Regional Blowing Dust 

Event
57

Figure 40. PM10 Annual Concentrations in Lamar during 2009.

233

106

138

73

111

171 173

118

144

176

98

79

0

50

100

150

200

250

Concentration ug/m3

Lamar PM10 2009

Lamar - Power Plant Lamar - Municipal Bldg.

174

All labeled data points are due to regional 

blowing dust events. Dates are adjacent. 

1/19/09

2/6/09

3/5/09

3/26/09

2/17/09

March 22 - 23, 2009 Regional Blowing Dust Event
58

Figure 41. PM10 Annual Concentrations in Steamboat Springs during 2009.

The monitoring data for 2009 as presented in figures 39, 40, and 41 clearly show that the PM10

exceedance at Pagosa Springs on March 22 and the high concentrations at Mount Crested Butte, Lamar, 

and Steamboat Springs were unusually high. Also, the 2009 charts show that all exceedances and most 

PM10 concentrations elevated above approximately 60 μg/m3, with a few minor exceptions, occurred 

during the January through March time frame. Each of the events identified on the charts above were 

analyzed by APCD meteorologists and scientists and each has been flagged as being caused by high 

wind/blowing dust events. 

The concentration of 255 μg/m3at Pagosa Springs was an exceptional event and the available monitoring 

date from other daily sites supports that the blowing dust event was spatially large covering a most of the 

southern and central parts of Colorado. The monitoring data on March 22 at Pagosa Springs was much 

higher than surrounding days and much higher than the entire year. A full statistical analysis of the PM10

monitoring data at Pagosa Springs is presented below. These data will demonstrate just how exceptional 

March 22, 2009 was and a ―but for‖ test is also presented in section 3.1 below to show that the PM10

exceedance at Pagosa Springs would not have occurred but for this large regional dust storm that was not 

reasonably controllable or preventable. 

Section 3.1 Historical Fluctuations of PM10 Concentrations Pagosa Springs

This historical fluctuation evaluation of PM10 monitoring data for sites affected by the March 22, 2009 

event was made using valid samples from PM10 samplers In Pagosa Springs. APCD has monitored PM10

in Pagosa Springs at two different sites (080070001 and 080070002) at various frequencies and intervals 

82 78

54 57

0

50

100

150

200

250

300

Concentration ug/m3

Steamboat Springs PM10 2009

Steamboat Springs

March 22, 2009 Regional 

April 8, 2009 Regional Blowing 

March 5, 2009 Eastern Colorado Regional 

Feb. 5-6, 2009 Eastern Colorado 

Note: Other elevated concentrations 
59

beginning in 1985. However, it‘s only been since 1992 that monitoring was performed with a consistent 

frequency (daily) and with sufficient completeness (> 75%) to satisfy data requirements for this analysis. 

Therefore, the data in this analysis is from both sites in Pagosa Springs beginning January 1992 through 

the end of 2009. The sites are spatially situated so that concerns regarding comparability between sites is 

minimal. There was no time period when data was taken at both sites simultaneously; however the data 

from each set reflect a similar distribution. The overall data summary is presented in Table 12, all data 

values are presented in μg/m3:

Table 12. PM10 Monitoring Data Summary for Pagosa Springs.

Summary - Entire Dataset

Pagosa Springs

Count 6096

Min 3

1 Q 18

Median 24

3 Q 36

Max 262

Mean 28.6

SD 17.6

Date Range 1992 - 2009

3/22/2009 255

The spatial scope of this event, addressed elsewhere in this document, was statewide and had an impact 

on PM10 concentrations at multiple sites. However, the 255 μg/m3at Pagosa Springs was the only site 

greater than the 150 μg/m3level of the NAAQS and is the only data set discussed in detail. A snapshot of 

data from those sites affected by the event is presented in Table 13, along with the approximate percentile 

value that data point represents for each site for their unique historical data sets, for the year of the event, 

and for the month.

Table 13. PM10 Monitoring Data Percentiles of Frequency for Other Areas with Elevated PM10.

Mt. Crested Butte Lamar Power Steamboat Springs

3/22/2009 (μg/m3) 93 111 54

Overall 99.6% 99.1% 90.6%

All March 99.8% 98.7% 67.0%

2009 99.8% 98.9% 94.0%

Additionally, the Pagosa Springs data set was summarized by month and year. These summaries (see 

Figures 42 through 44) present no obvious  ̳season‘; PM10 levels at any particular site in Colorado do not 

necessarily fluctuate by season. Of greater importance affecting day-to-day, typical PM10 concentrations 

are local sources, e.g. road sanding and sweeping, local burning from agriculture and residential heating, 

vehicle contributions via re-entrained road dust from paved and unpaved roads, track-out from unpaved 

lots, etc. While the historic monthly median values for Pagosa Springs are higher during the winter and 

spring months than the rest of the year there is little month-to-month variation. This time frame (winter 

and early spring) is that which is most likely to experience the meteorological and dry conditions 

exhibited during this event and discussed in section 2.0 of this document. The lack of variability between 
60

monthly medians suggests that typical data exhibiting regular variation are those in the inner-quartile 

range (i.e. between the 75th and 25th percentile). If a conservative approach is taken then a typical value 

should be no higher than the historic monthly 75th percentile value. The summary data for the month of 

March (all samples in any March) and for 2009 is presented in Table 14, in μg/m3:

Table 14. Pagosa Springs Month and Year PM10 Monitoring Data Summary.

March

(1992-2009) 2009

Count 524 354

Min 5 6

1 Q 20 16

Median 31 20

3 Q 44 26

Max 255 255

Mean 35.8 24.9

sd 23.1 23.4

Pagosa Springs – 080070001 and 080070002

The PM10 sample on March 22, 2009 at Pagosa Springs of 255 μg/m3exceeds the 99th percentile value

(107 μg/m3) for all March data, exceeds the 99th percentile value (138 μg/m3) for all 2009 data, and 

exceeds the 99th percentile value (56 μg/m3) for the entire dataset. Overall, this sample is the third highest 

sample in the entire data set, the highest sample in 2009, the maximum sample in any March, and exceeds 

the 99th percentile sample value for this site for all samples. The two samples in the entire data set greater 

than the event sample are 262 μg/m3(12/29/94) and 262 μg/m3(12/21/1994); both samples are associated 

with high wind events. There are 6096 samples in this dataset. The sample of March 22, 2009 clearly 

exceeds the typical samples for this site. This more than adequately, demonstrates that the high wind 

blowing dust event certainly affected air quality on March 22, 2009. 

Figures 42 through 44 graphically characterize the Pagosa Springs PM10 data. The first plot is the overall 

frequency histogram. The histogram displays a well-formed density function, almost 80% of the samples 

values are less than 40 μg/m3and over 90% of the samples are less than 50 μg/m3.
61

Figure 42. Pagosa Springs PM10 Histogram.

The monthly box-whisker plot in Figure 43 highlights the consistency of the majority of data from month 

to month. Note the greater variability (wider inner-quartile range) and greater range of the data through 

the winter and early spring months that‘s accompanied by typically greater monthly maxima. Recall, this 

time period experiences a greater number of days with meteorological conditions similar to those 

experienced on March 22, 2009. Although these high values affect the variability and central tendency of 

the dataset they aren‘t representative of what is typical at the site. 

Figure 43. Monthly Pagosa Springs PM10 Box and Whisker Plot.

0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

120.00%

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Frequency

Concentration (mg/m3)

Pagosa Springs PM10 Histogram

Frequency

Cumulative %

225, 03 Apr 2009

188, 25 Apr 2009

182, 06 Apr 2009 165, 12 Jun 2000

262, 29 Dec 1994

258, 21 Dec 1994

255, 22 Mar 2009

0

50

100

150

200

250

300

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
62

All the box plot features in this evaluation can be identifed with the following legend:

Where: 

1Q is the 25th percentile,

3Q is the 75th percentile vlaue and 

IQR is the interquartile range or the range of the middle 50% of a 

distribution (75th percentile vlaue – 25th percentile value). 

Additionally there are two types of outliers identifed in these plots: outliers greater than 3Q +1.5*IQR and 

outliers greater than 3Q + 3*IQR. The outliers that satisfy the last criteria are labeled with sample value 

and sample date for those samples greater than 150 μg/m3. Each of these outliers is associated with a 

known high-wind event similar to that of March 22, 2009. One sample, April 6, 2009, is believed to have 

been mislabeled by the operator and the sample actually was taken on the April 8, 2009 – corresponding 

to another high wind event.

The box plot of annual summaries may point to a trend of decreasing sample values, but without a similar 

decrease in the number of outliers. In 2009 there were more samples greater than 150 μg/m3than in any 

other year yet the variation in the data as measured by the IQR is less than that for any year except 2006. 

Each of these samples from 2009 is associated with an event similar to the one discussed here.

Figure 44. Annual Pagosa Springs PM10 Box and Whisker Plot.

262, 29 Dec

258, 21 Dec

165, 12 Jun

255, 22 Mar

225, 03 Apr

188, 25 Apr

182, 06 Apr

0

50

100

150

200

250

300

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
63

No Exceedance But For the Event

An estimation of PM10 due to the event is presented here. Based on the entirety of data in the Historical 

Summary (including multiple high wind events), a conservative estimate of the  ̳typical‘ values in March 

for Pagosa Springs would have been between 44 and 56 μg/m3corresponding to the 75th and 84th

Percentile values. Using these conservative values as  ̳typical‘ would indicate that the event provided an 

additional 199 – 211 μg/m3contribution from the 22-March event. Clearly, the sample from March 22, 

2009 exceeds what is typical for this site and ―but for‖ this large regional blowing dust storm Pagosa 

Springs would not have exceeded the 24-hour PM10 NAAQS.

Est. Conc. 

Above 

Typical 

(μg/m3Site )

Event Day 

Concentration 

(μg/m3)

March 

Median 

(μg/m3)

March 

Average 

(μg/m3)

March 

75th % 

(μg/m3)

March 

84th % 

(μg/m3)

Pagosa Springs 255 31 35.8 44 56 199 - 211

Table 15. Estimation of event PM10 totals for Pagosa Springs.

Section 3.2 Monitoring Data and Conclusions

Since the local anthropogenic sources are well controlled in Pagosa Springs and the surrounding area is 

covered by trees and other vegetation, and since the sustained surface wind speeds were well above 25 

mph in the region of the dust storm, it follows that the dust was transported into Pagosa Springs on March 

22, 2009. This high wind blowing dust event affected the air quality in Pagosa Springs and several other 

locations, including but not limited to Mount Crested Butte, Lamar, and Steamboat Springs, and Aspen 

(qualitatively) in the state of Colorado on March 22 and 23, 2009. The size and extent of the blowing 

dust storm made the event not preventable and it could not be reasonably controlled. Statistical data in 

section 3.1 above clearly shows that but for this high wind blowing dust event Pagosa Springs would not 

have exceeded the 24-hour NAAQS on March 22, 2009. 
64

4.0 News Accounts and Credible Evidence

Figure 45 is a copy of an email from Lee Cassin the Environmental Manager for Pitkin County Colorado. 

The email talks about ―brown snow‖. This snow was brown or reddish brown due to the dust that was 

lifted into the atmosphere in Arizona and New Mexico and then transported to the Aspen Colorado area 

by the same storm already described above. The dust was lifted over the frontal boundary where it was 

entrained into clouds associated with the dynamics of the storm. The dust was then scavenged by snow in 

the clouds and deposited on the ground with the rain and or snow that reached the ground. Figure 45 a. is 

an internal email discussing Cassin‘s query. Figure 46 is a similar notice from the Mt. Crested Butte 

Town Manager.

Figures 47, 48, and 49 are pictures of dust on cars in Aspen from the snow that Lee Cassin talks about. 

Figures 50, 51, and 52 are local news stories about the event. 

Figure 53 is the modeled snow depth for March 23, 2009, at 00Z (March 22, 5PM) in the Aspen area – for 

just prior to the onset of the evening rain/snow event in Aspen on March 22, 2009. It shows that, except 

for the valley running to the northwest from Aspen, the area was snow covered. This demonstrates that 

the dust in Lee Cassin‘s pictures did not come from the local area but was transported into the area with 

the strong southwesterly winds and transport regime already described in detail in this report. Since 

Aspen is 130 miles to the north of Pagosa Springs, the air mass with the suspended dust would have had 

to passed over the Pagosa Springs area before reaching Aspen. 
65

Figure 45. March 23, 2009, email from Lee Cassin, the Environmental Manager for Pitkin County,

Colorado.

From: "Lee Cassin" <Lee.Cassin@ci.aspen.co.us>

To: <ecmalone@cdphe.state.co.us>

Date: 3/23/2009 11:59 AM

Subject: natural dust event

Emmett,

This is just to let you know that last night we had a very unusual

weather event, and our office has been getting calls from citizens and

the media. We had winds the last couple of days (Sat. and Sun.), though

not extremely strong. Last night around 8 or so, it started raining and

then snowing, or rain mixed with snow. The next morning there was "brown

snow" everywhere. It looked like snowplows had coated everything with

brown road slush and sand. After the initial event, there was normal

snow, but the first frozen rain/snow was completely brown. I remember a

March event several years ago that created a lot of red dust, but this

was different in that it was brown, not red and happened at the

beginning of a snowstorm.

It might be interesting to look at the cocorahs network and see how many

reports there were.

Lee
66

From: GORDON Pierce

To: Malone, Emmett; McGraw, PAT

CC: Briggs, Kevin; Machovec, CHUCK; Reddy, Patrick

Date: 3/23/2009 12:11 PM

Subject: Re: Fwd: natural dust event

Three items that I see in the CoCoRaHS comments for this morning:

3/23/2009 CO-DL-8 Hotchkiss 9.0 WNW excellent dust storm yesterday afternoon, visibility down to

about 1 mile for a while. precipitation began as rain. 

3/23/2009 CO-EG-8 Wolcott 2.3 N High 62°F, Low 30°F, 7am 30°F; Cloud cover - 100% 4 miles visibility 

in very light drizzle; Last night about 11pm light snow fall and rain was very very dirty; leaving brown 

stain on shirt and cars. 

3/23/2009 CO-EG-21 Vail 0.9 WNW It is snowing hard at 7 am. The snow washed a lot of dirt out of the 

air. The collection samples were very dirty. 

Gordon

>>> Emmett Malone 3/23/2009 12:02 PM >>>

Thought you might like to see this.

Emmett

>>> "Lee Cassin" <Lee.Cassin@ci.aspen.co.us> 3/23/2009 11:58 AM >>>

Emmett,

This is just to let you know that last night we had a very unusual

weather event, and our office has been getting calls from citizens and

the media. We had winds the last couple of days (Sat. and Sun.), though

not extremely strong. Last night around 8 or so, it started raining and

then snowing, or rain mixed with snow. The next morning there was "brown

snow" everywhere. It looked like snowplows had coated everything with

brown road slush and sand. After the initial event, there was normal

snow, but the first frozen rain/snow was completely brown. I remember a

March event several years ago that created a lot of red dust, but this

was different in that it was brown, not red and happened at the

beginning of a snowstorm.

It might be interesting to look at the cocorahs network and see how many

reports there were.

Lee

Figure 45 a. Response to Cassin email.
67

From: "Joe Fitzpatrick" <JFitzpatrick@mtcrestedbutte-co.gov>

To: "RAY Mohr" <rmohr@smtpgate.dphe.state.co.us>

Date: 3/26/2009 11:04 AM

Subject: Mt. Crested Butte Wind Event

Hi Ray,

 I trust you are doing well. We are in the middle of a

great March Spring Snow Storm, 12 inches and still snowing!

 On March 22 and March 23, 2009 Mt. Crested Butte and

Gunnison County experienced a major wind event with the front edge of

this snow storm that blew a large amount of the red dust in from the

desert. So we had red dust ahead of and mixed with our snow last Monday

morning. Thus the monitors should have picked up a lot of red desert

dust and I just wanted you to make a note in your logs because it would

be great to see if there is a major spike in your dust readings.

 Have a great day!

Thanks,

Joe

Joseph W. Fitzpatrick, Jr.

Town Manager

P.O. Box 5800

Mt. Crested Butte, Colorado 81225

U.S.A.

970-349-6632

fax: 970-349-6326

www.mtcrestedbuttecolorado.us 

Figure 46. Mt. Crested Butte Town Manager description of the event.
68

Figure 47. Dust on vehicle in Aspen, Colorado, after the March 22, 2009 dust storm, from Lee Cassin,

the Environmental Manager for Pitkin County, Colorado. 
69

Figure 48. Dust on snow in Aspen, Colorado, after the March 22, 2009 dust storm, from Lee Cassin, the 

Environmental Manager for Pitkin County, Colorado. 
70

Figure 49. Dust on vehicle in Aspen, Colorado, after the March 22, 2009 dust storm, from Lee Cassin,

the Environmental Manager for Pitkin County, Colorado. 
71

Aspen still waiting for big snow

Aspen Times Staff Report

Aspen, CO Colorado

ARTICLE

COMMENTS

0

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ENLARGE

A robin, harbinger of spring, watches as winter returns to downtown Aspen Monday.

Janet Urquhart / The Aspen Times

ASPEN — A winter storm warning for parts of the Colorado Rockies, including the Aspen area, has been extended to 6 a.m. 

Tuesday, but only a few inches of new snow had materialized on local ski slopes by Monday morning.

The National Weather Service continues to call for heavy snow in the Colorado mountains, and rain or rain mixed with snow in 

the valleys, along with strong winds at higher altitudes that will result in blowing and drifting snow. Eight to 16 inches of new 

snow are possible by Tuesday morning, according to the weather service.

The storm warning was initially set to expire Monday at 6 p.m., but it has been extended to early Tuesday, as snow is now 

expected to continue through Monday night, the weather service said.

High winds ushered in the weather system on Sunday, stirring up dust out of the Southwest that coated Aspen ski slopes with a 

layer of brown grit. The brown was visible where ever ski tracks cut through the snowy overcoat early Monday and where 

grooming machines churned up the snow.

Aspen Mountain reported 4 inches of new snow on Monday morning; Highlands, Buttermilk and Snowmass all reported 3 inches. 

Most resorts around the state were reporting from 2 to 5 inches of new snow.

For Aspen, the weather service is predicting 4 to 7 inches on Monday, another 2 to 4 inches Monday night and a 60 percent 

chance of snow Tuesday with accumulations of about 1 inch. Highs of 25 to 35 are expected Monday and Tuesday, along with 

west winds of 10 to 15 mph both days.

Wednesday‟s forecast calls for a 40 percent chance of snow and highs in the 30s. Moderate snow accumulations are forecast on 

Wednesday night, and snow is likely Thursday with highs in the 20s, according to the weather service. Snow remains in the 

forecast Thursday night and Friday.

Figure 50. Aspen Times staff report.
72

What’s with the brown snow? Send us your news

Tuesday, April 7, 2009

Chris Outcalt

Vail Daily

Email Print

ENLARGE

Minturn resident John Knight took this picture of the Vail Valley's peculiar snow at his home Saturday

Special to the Daily / John Knight

The rust-tinged snow scattered around the Colorado mountains this past weekend had nothing to do with a volcano in Alaska, 

according to the National Weather Service.

The state‟s ski slopes were covered with dirty-looking snow on Saturday. And Chris Cuoco, a forecaster with the weather service 

in Grand Junction, said the rumors that the snow had ash from Southern Alaska‟s Mount Redoubt — which has erupted several 

times recently — in it are false.

“We heard that a lot, It‟s definitely not,” Cuoco said. “That volcano didn‟t produce anywhere near the ash necessary.”

Mount Redoubt is 100 miles southwest of Anchorage and tends to erupt every decade or so, belching ash for months. Geologists 

have recorded at least 19 eruptions since March 22, including one on Saturday.

But the weekend storm that hit the valley picked up dust from Arizona, Utah and western Colorado, giving it a rust color, Cuoco 

said.

“A lot of dirt and dust was carried into the atmosphere and suspended in it,” Cuoco said. “The snow and rain washed out a good 

portion of it out and you end up with pink snow falling.”

A similar storm hit the high country at the end of March.

“There was a decent content of red dust down by the Four Corners,” he said.

It‟s not unusual for a dirt-filled storm to hit the valley this time of year, Cuoco said.

“In the spring and fall the jet stream is directly of over us and the storms that move through usually have a lot of wind,” he said. 

“It sets up just right, with the very strong winds and dry conditions ahead of (the storm).”

It is possible for volcanic ash from west of the state to make its way to Colorado, but the eruption would have to be a lot bigger 

and the winds would have to be just right, Cuoco said.

The Associated Press contributed to this report.

Figure 51. Vail Daily news article.
73

Dust storms turn Aspen slopes brown Monday, March 23, 2009

Janet Urquhart

The Aspen Times

Aspen, CO Colorado

ARTICLE

COMMENTS

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ENLARGE

The lower slopes of Aspen Highlands take on a brownish hue Monday morning, the result of dust storms elsewhere.

Janet Urquhart / The Aspen Times

ASPEN — Despite a few inches of fresh snow Monday morning, Aspen‟s ski slopes sported an uncharacteristic brown hue, thanks to 

blustery winds carrying dirt from the Southwest and, perhaps, China.

Elsewhere in the Roaring Fork Valley, residents awoke to a spotty layer of dirt on their vehicles, thanks to precipitation that 

pulled the particles out of the air.

“When I looked at my car and my outdoor furniture, I thought, „Wow, we had brown snow,‟” said Jeff Hanle, Aspen Skiing Co. 

spokesman. “We‟re just thankful that it‟s snow.”

Dirt was deposited on the ski slopes and then covered over by the 3 to 4 inches that fell in Aspen and Snowmass on Sunday night. 

But, where snowcats churned up the surface, the dirt reappeared, giving groomers a brownish cast early Monday. Wherever 

skiers carved through the surface layer of white snow on ungroomed runs, brown appeared in their tracks. By afternoon, the 

bump runs on Aspen Mountain had a leopard-print look about them.

It‟s not the first time strong spring winds have carried dirt from elsewhere.

“We ended up with red snow one time,” Hanle recalled. “It all came from Utah.”

The dirt swirling in the air on Sunday wasn‟t local, either, according to Lee Cassin, environmental health director for the city of 

Aspen, Rather, the slopes were sporting grit from the desert Southwest, and possibly from as far away as China, where a huge 

plume of dust from a Gobi Desert sandstorm more than a week ago was carried aloft, she said.

It‟s not the first time sand from China has drifted around the globe and been pulled from the atmosphere with precipitation in 

Aspen, Cassin noted.

Closer to Colorado, wind-whipped dust storms in Utah, New Mexico and Arizona were undoubtedly a factor, as well, she said. In 

Colorado, Montrose and Cortez reported visibility of less than a mile on Sunday. In Grand Junction, wind gusts of up to 60 mph 

were recorded.

The winds came in advance of a winter storm that is expected to leave 8 to 16 inches of new snow in the Colorado mountains by

Tuesday morning, when a winter storm warning is to expire at 6 a.m. By midafternoon Monday, little of the predicted snow had 

fallen in Aspen, but the National Weather Service was continuing to call for significant snowfall.

janet@aspentimes.com

Figure 52. Aspen Times dust article.
74

Figure 53. National Operational Hydrologic Remote Sensing Center modeled snow cover for area near 

Aspen, Colorado for 00Z March 23, 2009 or 5 PM March 22, 2009 (http://www.nohrsc.noaa.gov/nsa/).
75

5.0 Local Dust Control

The following control measures resulted in the area‘s attainment of the PM10 NAAQS, and these 

measures should ensure continued maintenance of the PM10 NAAQS through the year 2021, which is the 

duration of the maintenance period.

1. Control of Emissions through Road Paving

The Town of Pagosa Springs paved 6.5 miles of unpaved roads during 1992, 1993, and 1994 in order 

to reduce PM10 emissions. This strategy was adopted locally in 1991 and included in State regulation 

in 1992 (Section I.B. of the ―State Implementation Plan-Specific Regulations for Nonattainment -

Attainment/Maintenance Areas (Local Elements)). The rule was approved by EPA in 1994 and was 

removed from the Colorado regulation in 2000 as the paving requirements had been completed.

2. Street Sanding Controls

There is a requirement that any user that applies street sanding material on Highway 160 and 

Highway 84 in the Pagosa Springs attainment/maintenance area must use materials containing less 

than one percent fines. Users of street sand on these highways must also use 15 percent less sand 

than an established base sanding amount. These strategies were adopted in 1992 and approved by 

EPA in 1994, and they are defined in detail in Sections I.B. and C., respectively, of the ―State 

Implementation Plan-Specific Regulations for Nonattainment - Attainment/Maintenance Areas (Local 

Elements) Regulations (5 CCR 1001-20).

3. Control of Emissions from Stationary Sources

Although there are no major stationary sources located in the Pagosa Springs attainment/maintenance 

area, the State‘s comprehensive permit rules will limit emissions from any new source that may, in 

the future, locate in the area. These rules include: 1) Regulation No. 3, "Air Pollution Emission 

Notices, Construction Permits and Fees, Operating Permits, and Including the Prevention of 

Significant Deterioration," 2) the ―Common Provisions" regulation, and 3) Regulation No. 6, 

―Standards of Performance for New Stationary Sources.‖

The Common Provisions, and Parts A and B of Regulation No. 3, are already included in the 

approved SIP. Regulation No. 6 implements the federal standards of performance for new stationary 

sources. The maintenance plan makes no changes to these regulations. This reference to Regulation 

No. 6 shall not be construed to mean that this regulation is included in the SIP.

As indicated above, emissions from new or modified major stationary sources emissions of PM10 are 

controlled under Regulation No. 3's nonattainment-area (NAA) new source review (NSR) permitting 

requirements. The NSR provisions require all new and modified major stationary sources to apply 

emission control equipment that achieves the "lowest achievable emission rate" (LAER) and to obtain 

emission offsets from other stationary sources of PM10.

The EPA approval of the original PM10 Maintenance Plan, effective on 08/14/2001, reinstates the 

prevention of significant deterioration (PSD) permitting requirements in the Pagosa Springs 

Attainment/Maintenance area. The federal PSD requirements are considered a relaxation from the 

NAA NSR requirements, as LAER is no longer required and is replaced by the less stringent "best 

available control technology" (BACT), along with the removal of the requirement to offset PM10

emissions. The future reapplication of NAA NSR provisions appears unlikely in the Pagosa Springs 

Attainment/Maintenance area based on current PM10 monitoring trends.
76

4. Federal Motor Vehicle Emission Control Program

The federal motor vehicle emission control program has reduced PM10 emissions through a 

continuing process of requiring diesel engine manufacturers to produce new vehicles that meet tighter 

and tighter emission standards. As older, higher emitting diesel vehicles are replaced with newer 

vehicles, the PM10 emissions in the Pagosa Springs area will be reduced.

5. Voluntary and State-Only Measures

In addition to the mandatory control measures discussed above, there are other activities that result in 

the reduction of PM10 emissions that are not classified as ―federally enforceable control measures.‖ 

Some notable examples include:

 The Town of Pagosa Springs has historically cleaned Highway 160 in town throughout the winter 

and spring using regenerative air vacuum sweepers. The frequency of this voluntary 

sweeping/cleaning has been about once after each street sanding deployment. For the future, the 

Town of Pagosa Springs has committed to regularly vacuum sweep/clean Highway 160 within 

four days of the roadway becoming free and clear of snow and ice following each street sanding 

deployment, as weather, temperature, and street conditions permit, between the intersections of 

Highway 84 to the east and 14th Street to the west.

 The Town of Pagosa Springs requires that all new developments have paved streets.

 The Town of Pagosa Springs encourages private businesses to properly clean/sweep private 

parking lots on a regular basis.

 Archuleta County commits to pave the unpaved portion of Hot Springs Boulevard from the 

existing pavement to the boundary of the airshed.

 Any owner or operator responsible for the construction or maintenance of any existing or new 

unpaved roadway which has vehicle traffic exceeding 200 vehicles per day in the 

attainment/maintenance area and surrounding areas must stabilize the roadway in order to 

minimize fugitive dust emissions. These State-wide requirements are defined in detail in Section 

III.D.2.a.(I) of the AQCC‘s Regulation No. 1.

These strategies are considered to be voluntary local initiatives and State-only requirements, and are 

intended to reduce PM10 emissions. These strategies are not intended to be federally enforceable.
77

6.0 Laboratory and Field Data 
78
79
80

7.0 Summary and Conclusions

Elevated 24-hour PM10 concentrations were recorded across much of Colorado. Except for the readings 

in the Denver metropolitan area, all of the March 22, 2009 twenty-four-hour PM10 concentrations were 

above the 90th percentile concentrations for their locations. The Pagosa Springs concentration exceeds 

the 99th percentile, and a conservative estimate of the dust storm contribution to the total concentration is 

199-211 μg/m3. This is evidence that the event was associated with a measured concentration in excess of 

normal historical fluctuations including background. But for the dust storm described in detail in this 

report, there would have been no exceedance on this day in Pagosa Springs.

This exceedance was the consequence of strong southwesterly winds in combination with dry conditions 

which caused significant blowing dust across much of northeast Arizona, northwest New Mexico, and 

southwest Colorado. Surface winds of 20 to 50 mph with gusts of 25 to 62 mph were recorded 

across the Four Corners region on March 22, 2009. These speeds are above the thresholds for 

blowing dust identified in EPA draft guidance and in detailed analyses completed by the State of 

Colorado.

Climatological data for March shows that most of the Four Corners area had received less than 50 

percent of the normal precipitation for the month and northeast Arizona was abnormally dry. Hopi in 

northeastern Arizona received only 0.17 inches of precipitation during the 30 days prior to March 22, 

2009. This total is well below the approximate threshold for blowing dust conditions at Hopi identified in 

the analysis contained in Attachment A. Both wind speeds and soil moisture in the Four Corners area 

and northeastern Arizona were conducive to the generation of significant blowing dust.

Friction velocities calculated for the region also help to explain why blowing dust originated in the Four 

Corners region and northeastern Arizona in particular. Even undisturbed desert soils normally resistant to 

wind erosion will be susceptible to blowing dust when friction velocities are greater than about 1.0 to 2.0 

meters per second. A wide area of Arizona and New Mexico had friction velocities well above 1.0 meters 

per second late in the day. Some of the highest values were within the Little Colorado River Valley and 

Painted Desert region of northeast Arizona. The computed friction velocities, measured wind speeds, and 

data on soil moisture conditions prove that this dust storm was a natural event that was not reasonably 

controllable or preventable.

Satellite imagery shows large plumes of southwest to northeast trending blowing dust in the Painted

Desert and Little Colorado River Valley region of northeastern Arizona on March 22, 2009. Forward and 

backward trajectories, wind streamline analyses, and surface and upper-level wind patterns show that this 

dust would have been transported into Colorado on March 22, 2009. An analysis run of a high-resolution 

meteorological model also shows winds flowing across northeast Arizona and Northwest New Mexico 

into Colorado. This analysis indicates that the zone of highest speeds targeted the Painted Desert and 

Little Colorado River Valley areas of northeastern Arizona – areas shown in Attachment A to be a 

significant source region for blowing dust transported into Colorado. Multiple sources of data and 

analyses of past dust storms in this area prove that this was a natural event and, more specifically, a 

significant natural dust storm originating in northeastern Arizona and northwestern New Mexico. But for 

the dust storm on March 22, 2009, this exceedance would not have occurred.

The Center for Snow and Avalanche Studies (http://www.snowstudies.org/index.html) has been studying 

the effects of desert dust deposition on snowpack albedo and snowmelt in the San Juan Mountains of 

Colorado. The center‘s log of events lists March 22, 2009 as one of twelve Dust-on-Snow events for the 

2008/2009 water year. Reports and photos from Pitkin County environmental health staff and other data 
81

indicate that desert dust from the Four Corners region moved as far north as Aspen, Colorado, during the 

evening of March 22. NOAA‘s Satellite Service Division also describes blowing dust moving from 

Arizona into southwest Colorado on March 22, 2009. Multiple reports from professional experts at other 

institutions substantiate the conclusion that this was a natural event. But for the dust storm on March 22, 

2009, this exceedance would not have occurred.
82

8.0 References

Colorado Department of Public Health and Environment, City of Lamar, Prowers County Commissioners, 

April 1998, Natural Events Action Plan for High Wind Events – Lamar, Colorado.

Draxler, R.R. and Rolph, G.D., 2012. HYSPLIT (HYbrid Single-Particle Lagrangian Integrated 

Trajectory) Model access via NOAA ARL READY Website (http://ready.arl.noaa.gov/HYSPLIT.php). 

NOAA Air Resources Laboratory, Silver Spring, MD.

Marticorena, B., G. Bergametti, D. Gillette, and J. Belnap, 1997, Factors controlling threshold friction 

velocity in semiarid and arid areas of the United States, Journal of Geophysical Research 102 D19, 

23,277-23,287.

Rolph, G.D., 2012. Real-time Environmental Applications and Display System (READY) Website 

(http://ready.arl.noaa.gov). NOAA Air Resources Laboratory, Silver Spring, MD.

Technical Services Program, Air Pollution Control Division, Colorado Department of Public Health and 

Environment, November 22, 2011,Technical Support Document for the January 19, 2009 Lamar 

Exceptional Event.

United States Environmental Protection Agency, May 2, 2011, draft Guidance on the Preparation 

of Demonstrations in Support of Requests to Exclude Ambient Air Quality Data Affected by 

High Winds under the Exceptional Events Rule..
83

Attachment A - Grand Junction, Colorado, Blowing Dust 

Climatology.
84

There can be significant transport of regional blowing dust into Grand Junction from source regions in 

Utah and Arizona. While there are sources for wind-blown dust within the Grand Valley and Grand 

Junction itself, there is evidence from the analysis of soil features, wind and precipitation climatology, 

and statistical analyses of Grand Junction exceedances of the PM10 standard that regional sources often 

play a significant role during these blowing dust events. This document provides a weight of evidence 

analysis for dust transport into Colorado.

Grand Junction, Colorado, is located in a part of the country that is largely arid to semi-arid. Figure A-1 

through A-3 show the annual average precipitation for Colorado, Arizona, and Utah, respectively. Grand 

Junction is in the Grand Valley of Western Colorado where the annual precipitation is typically less than 

10 inches. Northeastern Arizona, which is frequently upwind of Grand Junction during blowing dust 

events, receives between 5 and 15 inches of precipitation each year. The Colorado River Basin in eastern 

and southeastern Utah, which is also frequently upwind of Grand Junction during blowing dust events, 

also receives 5 to 10 inches per year.

Figure A-4 shows the 1971-2000 monthly normal precipitation amounts for Grand Junction, Colorado. 

The annual average for this time period is 8.99 inches. The wettest months are March through May and 

August through October. The driest months are January, February, June, July, November, and December. 

These months receive an average of 0.57 inches per month. The annual monthly average precipitation is 

0.75 inches.

Arid to semi-arid soils make much of the region susceptible to blowing dust. The map in Figure A-5 

shows that portion of the Colorado Plateau (circled in red) where modern wind erosion features are 

common and clearly visible in Google Earth images. These features include longitudinal dunes and other 

sand or soil erosion structures with a predominant southwest to northeast orientation. This orientation is 

the result of the predominant southwesterly flow that occurs during high wind and blowing dust events in 

the region. Figures A-6 through A-12 present aerial views of ubiquitous erosion features in northeastern 

Arizona and southeastern Utah. The Painted Desert of northeastern Arizona is frequently the source for 

much of the blowing dust in the Four Corners region. Figure A-13 provides a particularly good satellite 

image of a blowing dust event originating in the Painted Desert and extending northeastward across the 

junction of the Four Corners (source: NASA Tera satellite, http://earthobservatory.nasa.gov/IOTD/view.php?id=37791). 

Strong southwesterly winds caused this blowing dust event.

The text that accompanies this image on NASA‘s Earth Observatory 10th Anniversary page follows 

below:

―A dust storm struck northeastern Arizona on April 3, 2009. With winds over 145 kilometers (90 

miles) per hour reported near Meteor Crater, east of Flagstaff, the storm reduced visibility and 

forced the temporary closure of part of Interstate 40, according to The Arizona Republic.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA‘s Terra satellite 

captured this image on April 3, 2009. Clear skies allow a view of multiple source points of this 

dust storm. The source points occur along an arc that runs from northwest to southeast.

This dust storm occurred in the area known as Arizona‘s Painted Desert, and the dust plumes 

show why. Whereas many dust plumes are uniform in color, these plumes resemble a band of 

multicolored ribbons, ranging from pale beige to red-brown, reflecting the varied soils from 

which the plumes arise. The landscapes of the Painted Desert are comprised mostly of Chinle 

Formation rocks—remains of sediments laid down during the time of the first dinosaurs, over 200 

million years ago.‖
85

Figure A-1. Average annual precipitation in Colorado based on 1961-1990 normals.
86

Figure A-2. Average annual precipitation in Arizona based on 1961-1990 normals.
87

Figure A-3. Average annual precipitation in Utah based on 1961-1990 normals.
88

Figure A-4. 1971-2000 monthly normal precipitation in Grand Junction Colorado. 

Figure A-5. The portion of the Colorado Plateau in Utah, Arizona, and New Mexico that exhibits 

widespread surface soil and sand erosion features in Google Earth imagery. Much of the highlighted area 

within Arizona is within the Painted Desert.

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1 2 3 4 5 6 7 8 9 10 11 12

Precipitation - Inches

Month

Grand Junction 1971-2000
89

Figure A-6. Southwest to northeast soil and sand erosion structures in southeastern Utah.

Figure A-7. Southwest to northeast soil and sand erosion structures in northeastern Arizona (Painted 

Desert).
90

Figure A-8. Southwest to northeast soil and sand erosion structures in southeastern Utah.

Figure A-9. Southwest to northeast soil and sand erosion structures in northeastern Arizona (Painted 

Desert). The slip faces of dunes (lighter bands) face in the direction of wind flow – toward the northeast.
91

Figure A-10. Southwest to northeast soil and sand erosion structures in southeastern Utah.

Figure A-11. Southwest to northeast soil and sand erosion structures in northeastern Arizona (Painted 

Desert). 
92

Figure A-12. Southwest to northeast soil and sand erosion structures in northeastern Arizona (Painted 

Desert).
93

Figure A-13. NASA Tera satellite image of a dust storm on April 3, 2009, in southwesterly flow over the 

Painted Desert of northeastern Arizona (http://earthobservatory.nasa.gov/IOTD/view.php?id=37791). 
94

Figure A-14 displays the surface weather map for this event (00Z April 4, 2009, or 5 PM MST April 3, 

2009). A strong low pressure system in southern Colorado, strong southwesterly winds in the Four 

Corners area, and the blowing dust symbol (infinity sign) at Farmington (New Mexico) and Cortez 

(Colorado) are evident in this map. Blowing dust in this region is frequently associated with 

southwesterly flow.

Figure A-14. Surface weather map for 00Z April 4, 2009, (5 PM MST April 3, 2009), showing a strong 

low pressure system in southern Colorado, strong southwesterly winds in the Four Corners area and the 

blowing dust symbol (infinity sign) at Farmington (New Mexico) and Cortez (Colorado).

A USGS map of the Colorado Plateau in Figure A-15 shows the prevalence of eolian or wind-blown sand 

deposits in southeastern Utah and northeastern Arizona. An analysis of the annual frequency of dust 

storms (Orgill and Sehmel, 1976) in the western half of the U.S. suggests that portions of eastern and 

western Utah and northeastern Arizona are source regions for blowing dust (see Figure A-16). Soil and 

sand structures point to the prevalence of southwesterly flow during blowing dust events, and 

precipitation climatology highlights the potential for blowing dust across much of the region. In 

addition, an analysis of back trajectories associated with high PM10 concentration events in Grand 

Junction discussed in the next section of this document supports the conclusion that soils in Arizona and 

Utah are likely significant contributors to PM10 measured during many dust storms affecting Grand 

Junction.
95

Figure A-15. USGS map of eolian sand features on the Colorado Plateau 

(http://geochange.er.usgs.gov/sw/impacts/geology/sand/ ).
96

Figure A-16. Number of dust storms per year from: Orgill, M.M., Sehmel, G.A., 1976. Frequency and 

diurnal variation of dust storms in the contiguous USA. Atmospheric Environment 10, 813–825.

NOAA HYSPLIT 36-hour back trajectories were calculated for Grand Junction for the eight 24-hour 

periods from 2004 through early 2009 with the Powell monitor PM10 concentrations in excess of 75 

μg/m3, strong regional winds, and dry soils. Trajectories were modeled every 4 hours for each day. Data 

presented later in this document provides evidence that the moderate to high PM10 levels on these days 

were from blowing dust. The 6 back trajectories for each day were calculated for an arrival height of 500 

meters using EDAS40 data and model vertical velocities (see: http://www.arl.noaa.gov/HYSPLIT.php ). 

The eight days used in the analysis and the Powell monitor concentrations measured on these days are 

presented in Table A-1. 

The back trajectories for these high-concentration days are shown in Figure A-17. Transport was 

generally from the west through southwest. A high density of trajectory points is found in northeast 

Arizona and southeast Utah. Most of these trajectories in Figure A-17 are also consistent with transport 
97

from or across suspected or known blowing dust source regions highlighted in Figures A-5, A-13, A-15, 

and A-16.

Table A-1. Grand Junction Powell monitor days with concentrations in excess of 75 μg/m3and blowing 

dust conditions (from 2004 through early 2009).

Year Month Day

Powell 24-hour PM10 concentration 

in μg/m3

2005 4 19 197.8

2008 4 15 116.1

2008 4 21 103.6

2004 9 3 102

2006 3 3 98.3

2008 5 21 86.7

2008 4 30 83.5

2006 6 7 77.9

Figure A-17. NOAA HYSPLIT 36-hour back trajectories for Grand Junction for those eight 24-hour periods from 

2004 through early 2009 with the Powell monitor PM10 concentrations in excess of 75 μg/m3, strong regional 

winds, and dry soils. Trajectory points are sized and color-coded to reflect 24-hour PM10 concentrations in μg/m3. 

Trajectories were calculated every 4 hours for each day. 
98

The trajectories in Figure A-17 point to the possibility that, at times, dust from Utah and Arizona can have a 

major impact on Grand Junction and less of an impact elsewhere in western Colorado. This non-homogeneity is 

possible given the fact that dust storms are frequently organized into discreet plumes from discreet areas that 

maintain their integrity for long distances. An example of this can be seen in Figure A-18 that shows plumes of 

dust in New Mexico during a windstorm on May 20, 2008.

Figure A-19 shows the NOAA HYSPLIT back trajectories for the highest concentration day during the 2004 

through early 2009 period: April 19, 2005. Twenty-four hour back trajectories for each hour during the period 

with high winds (using EDAS40 data and 500-meter arrival heights) show that the back trajectories for Grand 

Junction were more likely to have crossed the Painted Desert and southeastern Utah than those for Telluride and 

Durango, which measured lower PM10 concentrations on this day.

Figure A-18. Discreet plumes of blowing dust in New Mexico, Mexico, and Arizona visible in GOES satellite 

imagery for May 20, 2008 (http://www.osei.noaa.gov/Events/Dust/US_Southwest/2008/DSTusmx142_G12.jpg).

K-means cluster analysis has been applied to Grand Junction Powell PM10 concentrations, Grand Junction and 

Painted Desert 30-day total precipitation for each PM10 monitoring day, and Grand Junction and Painted Desert 

daily maximum wind gust speeds for each monitoring day. K-means cluster analysis is a statistical method for 

identifying clusters or groupings of values for many variables. For environmental variables, these clusters often 

represent distinct processes, conditions, or events. In this case, cluster analysis differentiates PM10 concentrations 

associated with strong winds, low soil moistures, and blowing dust by providing mean values for these 5 variables 

for 5 distinct categories of PM10 events. The period of record considered was from January 2004 through March 
99

2009. The Hopi weather station located in the central portion of the Painted Desert was used to represent Painted 

Desert conditions in northeastern Arizona, and the Grand Junction National Weather Service station was used to 

represent Grand Junction conditions. The 30-day total precipitation values appear to be a better metric for 

blowing dust conditions than shorter-term totals.

Figure A-19. 24-hour NOAA HYSPLIT back trajectories for every hour from 1500 MST to 2200 MST for Grand 

Junction (red), Telluride (green), and Durango (blue) for the dust storm of April 19, 2005.

The results of the cluster analysis are presented in Table A-2 below. Cluster 1 represents high soil moisture 

conditions, moderate gust speeds, and low PM10 concentrations. Cluster 2 represents very low soil moisture, 

moderate PM10, and low gust speeds. Cluster 3 represents low soil moisture, moderate gusts, and low PM10. 

Cluster 4 represents moderate soil moisture, low gusts, and low PM10. Finally, Cluster 5 represents high PM10, 

high gusts, and low soil moisture. Cluster numbers, Grand Junction Powell PM10 concentrations, and Grand 

Junction daily maximum gust speeds are plotted in Figure A-20.

The data in Figure A-20 clearly show that the highest PM10 concentrations tend to occur in Cluster 5 with gusts 

above 40 mph. The only exceedance in this period occurred on a day with a peak gust of 43 mph. Cluster 2 is 

likely to be indicative of wintertime inversion conditions with lighter winds and moderately elevated PM10. 

Figure A-21 shows the concentrations and cluster values associated with Hopi station daily maximum gust 

speeds. The overall pattern is similar. The highest concentration day is associated with a peak gust of 47 mph at 

Hopi. All of the days/events presented in Figure A-17, A-19, and Table A-1 were classified as Cluster 5.
100

Table A-2. K-means cluster analysis means for Grand Junction PM10 and meteorological variables.

Cluster Variables

Cluster 1 

Means

Cluster 2 

Means

Cluster 3

Means

Cluster 4

Means

Cluster 5

Means

Powell 24-hour PM10 in μg/m3

24.5 37.3 24.3 21.8 74.9

Hopi Wind Gust in mph 20.8 18.0 32.5 20.7 40.5

Grand Junction Wind Gust in mph 20.4 16.5 31.8 19.6 43.1

Grand Junction 30-day 

Precipitation 1.7 0.4 0.5 0.8 0.6

Hopi 30-day Precipitation 1.8 0.2 0.5 0.7 0.3

Count 85 120 170 147 24

Figure A-20. Grand Junction Powell 24-hour PM10 concentrations versus Grand Junction gust speed by 

cluster.

Figures A-22 and A-23 show Powell PM10 concentrations versus Grand Junction and Hopi 30-day 

precipitation totals, respectively, by cluster. The blowing dust group, Cluster 5, is generally associated 

with 30-day precipitation totals of less than 1.00 inches at Grand Junction and less than 0.50 inches at 

Hopi. While this is not proof that the measured dust in Grand Junction is from Arizona, it adds to the 

weight of evidence that the Painted Desert makes a significant contribution to PM10 concentrations in 

Grand Junction during many blowing dust events. Of interest in this regard are the two high 

concentrations (greater than 100 μg/m3) that occurred when Grand Junction 30-day precipitation totals 

were greater than an inch (see Figure A-22). One of these occurred when transport was from the 

0

50

100

150

200

250

051 01 52 02 53 03 54 04 55 05 56 0

Grand Junction Gust Speed in mph

Grand Junction Powell 24-hr PM10 - ug/m3

Clusters

1

4

2

3

5
101

southwest. On this day (April 21, 2008) the NOAA Satellite Smoke Text Archive reported the following 

(see http://www.ssd.noaa.gov/PS/FIRE/smoke.html ):

―Blowing dust is seen over most of Utah (and part of western Nevada) and the dust is moving toward the 

northeast, reaching into northwestern Colorado and southern Wyoming.‖

Figure A-21. Grand Junction Powell 24-hour PM10 concentrations versus Hopi gust speed by cluster.

0

50

100

150

200

250

051 01 52 02 53 03 54 04 55 05 56 0

Hopi Gust Speed in mph

Grand Junction Powell 24-hr PM10 - ug/m3

Clusters

3

4

5

1

2
102

Figure A-22. Grand Junction Powell 24-hour PM10 concentrations versus Grand Junction 30-day total 

precipitation by cluster.

Figure A-23. Grand Junction Powell 24-hour PM10 concentrations versus Hopi 30-day total precipitation 

by cluster.

0

50

100

150

200

250

0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.000

Grand Junction 30-day Precipitation in Inches

Grand Junction Powell 24-hr PM10 - ug/m3

Clusters

4

2

3

1

5

0

50

100

150

200

250

0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.000

Hopi 30-day Precipitation in Inches

Grand Junction Powell 24-hr PM10 - ug/m3

Clusters

3

4

5

1

2
103

The other occurred on April 15, 2008, when the flow was from Arizona and southeast Utah. The transport 

conditions, the discrepancy between high recent precipitation in Grand Junction and low recent precipitation at 

Hopi for these two days, and, in one case, analyst discussion of what was visible in satellite images suggest that 

much of the dust might have originated from outside of the Grand Junction environment. 

Figure A-24 shows Grand Junction Powell 24-hour PM10 concentrations versus peak gust wind directions at the 

Little Delores RAWS weather station about 25 miles west-southwest of Grand Junction. Grand Junction is 

situated on the floor of the Grand Valley, a major northwest to southeast trending basin than can force or channel 

synoptic scale flows. As a result, surface wind directions in Grand Junction may not be useful indicators of the 

direction of longer-range transport. Little Delores is on the Uncompahgre Plateau, and winds here are more likely 

to reflect the larger-scale transport directions for the region. This graph indicates that high PM10 at Grand 

Junction (Cluster 5) is associated with winds from the south-southeast to west-southwest at Little Delores. These 

directions point to dust sources in southeast Utah and northeastern Arizona. This is further evidence that dust 

from these areas may make a significant contribution to PM10 measured in Grand Junction during blowing dust 

events.

Figure A-24. Grand Junction Powell 24-hour PM10 concentrations versus peak gust wind directions at the Little 

Delores RAWS weather station, by cluster.

Figure A-25 presents monthly percentiles for Grand Junction gust speeds. Wind gusts generally considered to be 

high enough for significant blowing dusts (40 mph or higher) are within the upper 5 to 15 percent during each 

month of the year. Consequently, these events can be viewed as exceptional rather than normal. Gusts in this 

category can occur any month of the year, but are most likely in March, April, May and October. Figure A-4 

shows that in Grand Junction these are typically among the wettest months of the year. It is in drier years, 

therefore, that blowing dust may be most prevalent during the spring and fall months. January, February, and 

June are typically very dry, and might be expected to have a significant proportion of blowing dust events.

Figures A-26 and A-27 show histograms for Grand Junction and Hopi wind gusts, respectively. The 95th

0

50

100

150

200

250

03 06 09 0120150180210240270300330360

Little Delores Gust Direction

Grand Junction Powell 24-hr PM10 - ug/m3

Clusters

1

4

2

3

5
104

percentile gust speed for Grand Junction is 43 mph. For Hopi it is 41 mph. For both sites, it is clear that gusts in 

the range that is associated with blowing dust are the exception rather than the rule. Cluster analysis also shows 

that the blowing dust events represent only 4% of the PM10 sample days (from Table A-2, Cluster 5 had 24 cases 

out of a total of 546). The weight of evidence presented in this document clearly suggests that source regions in 

Arizona and Utah can have a significant impact on PM10 concentrations in Grand Junction during blowing dust 

events and that these events occur when dry soils are affected by winds of exceptional strength. Control of these 

sources, which are outside of Colorado, may not be reasonably achievable or possible.

The precipitation climatology for the Four Corners area indicates that the area can be susceptible to blowing 

dust when winds are high. Landform imagery shows that northeastern Arizona and southeastern Utah in 

particular have experienced a long-term pattern of wind erosion and blowing dust when winds have been 

southwesterly and blowing into western and southern Colorado. Back trajectories, case studies, satellite 

imagery, and statistical analyses have also shown that northeastern Arizona and southeastern Utah are a 

significant source for blowing dust transported into Colorado. Elevated PM10 in Grand Junction during 

windstorms is generally associated with wind gusts of 40 mph or higher at Grand Junction and Hopi in 

northeastern Arizona and southwesterly flow in Grand Junction. Elevated PM10 in Grand Junction is generally 

associated with 30-day precipitation totals of less than 1.00 inches at Grand Junction and less than 0.50 inches at Hopi.

Reference:

Orgill, M.M., Sehmel, G.A., 1976. Frequency and diurnal variation of dust storms in the contiguous USA. 

Atmospheric Environment 10, 813–825

Figure A-25. Percentile plot of Grand Junction daily maximum 5-second gust speed in miles per hour 

showing that gusts of 40 mph or greater always occur within the top 15 percentile speeds for each month 

of the year.

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11 12

Percentile Plot

Grand Junction Daily Max 5-second Gust in mph

Month

Gust Speed in mph

Top 15% in Red, Lower 15% in Blue, Median Orange

January 2004-February 2009
105

Figure A-26. Histogram of daily maximum 5-second wind gusts at Grand Junction based on January 2004 –

February 2009.

Figure A-27. Histogram of daily maximum 5-second wind gusts at Hopi based on January 2004 – February 2009.

0

71

143

214

286

357

429

500

0 10 20 30 40 50 60 70

Daily Max 5-second Gust in mph

Count

0

43

86

129

171

214

257

300

0 10 20 30 40 50 60 70

Daily Max Gust in mph

Count
106

Attachment B - Southwest Surface Analysis:

0600Z March 22, 2009 (11 PM MST March 21, 2009) 

through 0600Z March 23, 2009 (11 PM MST March 21, 2009).
107

Southwest Surface analysis for 0600Z March 22, 2009, or 11 PM MST March 21, 2009 

(http://nomads.ncdc.noaa.gov/ncep/NCEP). 

Southwest Surface analysis for 0900Z March 22, 2009, or 2 AM MST March 22, 2009 

(http://nomads.ncdc.noaa.gov/ncep/NCEP). 
108

Southwest Surface analysis for 1200Z March 22, 2009, or 5 AM MST March 22, 2009 

(http://nomads.ncdc.noaa.gov/ncep/NCEP). 

Southwest Surface analysis for 1500Z March 22, 2009, or 8 AM MST March 22, 2009 

(http://nomads.ncdc.noaa.gov/ncep/NCEP). 
109

Southwest Surface analysis for 1800Z March 22, 2009, or 11 AM MST March 22, 2009 

(http://nomads.ncdc.noaa.gov/ncep/NCEP). 

Southwest Surface analysis for 2100Z March 22, 2009, or 2PM MST March 22, 2009 

(http://nomads.ncdc.noaa.gov/ncep/NCEP). 
110

Southwest Surface analysis for 0000Z March 23, 2009, or 5PM MST March 22, 2009 

(http://nomads.ncdc.noaa.gov/ncep/NCEP).

Southwest Surface analysis for 0300Z March 23, 2009, or 8PM MST March 22, 2009 

(http://nomads.ncdc.noaa.gov/ncep/NCEP).
111

Southwest Surface analysis for 0600Z March 23, 2009, or 11PM MST March 22, 2009 

(http://nomads.ncdc.noaa.gov/ncep/NCEP).
112

Attachment C - Hourly Surface Streamlines:

12 Z March 22, 2009 (5 AM MST March 22, 2009) 

through 06 Z March 23, 2009 (11 PM MST March 22, 2009).
113

Southwest Streamline Analysis for 1200Z March 22, 2009, or 5 AM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).

Southwest Streamline Analysis for 1300Z March 22, 2009, or 6 AM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
114

Southwest Streamline Analysis for 1400Z March 22, 2009, or 7 AM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).

Southwest Streamline Analysis for 1500Z March 22, 2009, or 8 AM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
115

Southwest Streamline Analysis for 1600Z March 22, 2009, or 9 AM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).

Southwest Streamline Analysis for 1700Z March 22, 2009, or 10 AM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
116

Southwest Streamline Analysis for 1800Z March 22, 2009, or 11 AM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).

Southwest Streamline Analysis for 1900Z March 22, 2009, or 12 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
117

Southwest Streamline Analysis for 2000Z March 22, 2009, or 13 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).

Southwest Streamline Analysis for 2100Z March 22, 2009, or 2 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
118

Southwest Streamline Analysis for 2200Z March 22, 2009, or 3 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).

Southwest Streamline Analysis for 2300Z March 22, 2009, or 4 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
119

Southwest Streamline Analysis for 0000Z March 23, 2009, or 5 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).

Southwest Streamline Analysis for 0100Z March 23, 2009, or 6 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
120

Southwest Streamline Analysis for 0200Z March 23, 2009, or 7 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).

Southwest Streamline Analysis for 0300Z March 23, 2009, or 8 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
121

Southwest Streamline Analysis for 0400Z March 23, 2009, or 9 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).

Southwest Streamline Analysis for 0500Z March 23, 2009, or 10 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
122

Southwest Streamline Analysis for 0600Z March 23, 2009, or 11 PM MST March 22, 2009 

(http://vortex.plymouth.edu/u-make.html).
123

Attachment D - Weather Warnings and Advisories from the 

National Weather Service Forecast Offices in

Grand Junction, Colorado, Flagstaff, Arizona, and

Albuquerque, New Mexico for March 22, 2009.
124

Weather Warnings and Advisories from http://has.ncdc.noaa.gov.

 NWS SRRS PRODUCTS FOR:

 2009032200 to 2009032400

Flagstaff Arizona National Weather Service Forecast Office

WWUS75 KFGZ 220450

NPWFGZ

URGENT - WEATHER MESSAGE

NATIONAL WEATHER SERVICE FLAGSTAFF AZ

950 PM MST SAT MAR 21 2009

AZZ004>011-015>018-037>039-221300-

/O.CON.KFGZ.WI.Y.0005.090322T1600Z-090323T0600Z/

KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRYCOCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINSNORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARD-CHINLE VALLEYCHUSKA MOUNTAINS AND DEFIANCE PLATEAU-WESTERN MOGOLLON RIMEASTERN MOGOLLON RIM-WHITE MOUNTAINS-NORTHERN GILA COUNTYYAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONSBLACK MESA AREAINCLUDING THE CITIES OF...JACOB LAKE...FREDONIA...PAGE...

LEES FERRY...GRAND CANYON VILLAGE...SUPAI...NORTH RIM...VALLE...

PRESCOTT...SELIGMAN...ASH FORK...KEAMS CANYON...KAIBITO...

CANYON DE CHELLY...CHINLE...KAYENTA...WINDOW ROCK...GANADO...

FLAGSTAFF...WILLIAMS...MUNDS PARK...HEBER...HAPPY JACK...

FOREST LAKES...SHOW LOW...GREER...PINETOP...PAYSON...STRAWBERRY...

YOUNG...COTTONWOOD...CAMP VERDE...CORDES JUNCTION...BAGDAD...

SEDONA...NAVAJO N.M.

950 PM MST SAT MAR 21 2009

...WIND ADVISORY REMAINS IN EFFECT FROM 9 AM TO 11 PM MST

SUNDAY...

A WIND ADVISORY REMAINS IN EFFECT FROM 9 AM TO 11 PM MST SUNDAY.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN SUNDAY WILL

BRING STRONG WINDS TO NORTHERN ARIZONA. BEGINNING LATE SUNDAY

MORNING...SOUTHWEST WINDS WILL INCREASE TO 30 TO 40 MPH WITH

GUSTS FROM 45 TO 55 MPH OVER MUCH OF THE AREA. THESE STRONG WINDS ARE

ANTICIPATED TO CONTINUE INTO THE LATE EVENING HOURS AS THE STORM

SYSTEM MOVES THROUGH THE AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WIND ADVISORY MEANS THAT SUSTAINED WINDS OF 30 TO 39 MPH...OR

GUSTS FROM 40 TO 57 MPH...ARE EXPECTED. WINDS THIS STRONG CAN

MAKE DRIVING DIFFICULT...ESPECIALLY FOR HIGH PROFILE VEHICLES.

CONSIDER SECURING LOOSE BELONGINGS ON YOUR PROPERTY. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

AZZ012>014-040-221300-

/O.CON.KFGZ.HW.A.0001.090322T1600Z-090323T0600Z/

LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTYLITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTYLITTLE COLORADO RIVER VALLEY IN APACHE COUNTYNORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-

INCLUDING THE CITIES OF...WUPATKI N.M....TUBA CITY...WINSLOW...

HOLBROOK...SNOWFLAKE...ST. JOHNS...SPRINGERVILLE...DILKON...

KYKOTSMOVI

950 PM MST SAT MAR 21 2009

...HIGH WIND WATCH REMAINS IN EFFECT FROM 9 AM MST SUNDAY THROUGH
125

SUNDAY EVENING...

A HIGH WIND WATCH REMAINS IN EFFECT FROM 9 AM MST SUNDAY THROUGH

SUNDAY EVENING.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN SUNDAY

WILL BRING VERY STRONG WINDS TO PORTIONS OF NORTHERN ARIZONA.

BEGINNING LATE SUNDAY MORNING...SOUTHWEST WINDS WILL INCREASE TO

40 TO 50 MPH WITH GUSTS UP TO 65 MPH OVER THE LITTLE COLORADO

RIVER VALLEY AND ADJACENT AREAS. EXPECT WIND SPEEDS TO DIMINISH

SUNDAY EVENING AS THE SYSTEM MOVES EASTWARD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WATCH MEANS THERE IS THE POTENTIAL FOR A HAZARDOUS

HIGH WIND EVENT...WITH SUSTAINED WINDS GREATER THAN 40 MPH...OR

GUSTS GREATER THAN 58 MPH. MONITOR THE LATEST FORECASTS AND

WARNINGS FOR UPDATES ON THIS SITUATION. ADDITIONAL WEATHER

INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

WWUS75 KFGZ 220450

NPWFGZ

URGENT - WEATHER MESSAGE

NATIONAL WEATHER SERVICE FLAGSTAFF AZ

950 PM MST SAT MAR 21 2009

AZZ004>011-015>018-037>039-221300-

/O.CON.KFGZ.WI.Y.0005.090322T1600Z-090323T0600Z/

KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRYCOCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINSNORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARD-CHINLE VALLEYCHUSKA MOUNTAINS AND DEFIANCE PLATEAU-WESTERN MOGOLLON RIMEASTERN MOGOLLON RIM-WHITE MOUNTAINS-NORTHERN GILA COUNTYYAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONSBLACK MESA AREAINCLUDING THE CITIES OF...JACOB LAKE...FREDONIA...PAGE...

LEES FERRY...GRAND CANYON VILLAGE...SUPAI...NORTH RIM...VALLE...

PRESCOTT...SELIGMAN...ASH FORK...KEAMS CANYON...KAIBITO...

CANYON DE CHELLY...CHINLE...KAYENTA...WINDOW ROCK...GANADO...

FLAGSTAFF...WILLIAMS...MUNDS PARK...HEBER...HAPPY JACK...

FOREST LAKES...SHOW LOW...GREER...PINETOP...PAYSON...STRAWBERRY...

YOUNG...COTTONWOOD...CAMP VERDE...CORDES JUNCTION...BAGDAD...

SEDONA...NAVAJO N.M.

950 PM MST SAT MAR 21 2009

...WIND ADVISORY REMAINS IN EFFECT FROM 9 AM TO 11 PM MST

SUNDAY...

A WIND ADVISORY REMAINS IN EFFECT FROM 9 AM TO 11 PM MST SUNDAY.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN SUNDAY WILL

BRING STRONG WINDS TO NORTHERN ARIZONA. BEGINNING LATE SUNDAY

MORNING...SOUTHWEST WINDS WILL INCREASE TO 30 TO 40 MPH WITH

GUSTS FROM 45 TO 55 MPH OVER MUCH OF THE AREA. THESE STRONG WINDS ARE

ANTICIPATED TO CONTINUE INTO THE LATE EVENING HOURS AS THE STORM

SYSTEM MOVES THROUGH THE AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WIND ADVISORY MEANS THAT SUSTAINED WINDS OF 30 TO 39 MPH...OR

GUSTS FROM 40 TO 57 MPH...ARE EXPECTED. WINDS THIS STRONG CAN

MAKE DRIVING DIFFICULT...ESPECIALLY FOR HIGH PROFILE VEHICLES.

CONSIDER SECURING LOOSE BELONGINGS ON YOUR PROPERTY. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&
126

$$

AZZ012>014-040-221300-

/O.CON.KFGZ.HW.A.0001.090322T1600Z-090323T0600Z/

LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTYLITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTYLITTLE COLORADO RIVER VALLEY IN APACHE COUNTYNORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-

INCLUDING THE CITIES OF...WUPATKI N.M....TUBA CITY...WINSLOW...

HOLBROOK...SNOWFLAKE...ST. JOHNS...SPRINGERVILLE...DILKON...

KYKOTSMOVI

950 PM MST SAT MAR 21 2009

...HIGH WIND WATCH REMAINS IN EFFECT FROM 9 AM MST SUNDAY THROUGH

SUNDAY EVENING...

A HIGH WIND WATCH REMAINS IN EFFECT FROM 9 AM MST SUNDAY THROUGH

SUNDAY EVENING.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN SUNDAY

WILL BRING VERY STRONG WINDS TO PORTIONS OF NORTHERN ARIZONA.

BEGINNING LATE SUNDAY MORNING...SOUTHWEST WINDS WILL INCREASE TO

40 TO 50 MPH WITH GUSTS UP TO 65 MPH OVER THE LITTLE COLORADO

RIVER VALLEY AND ADJACENT AREAS. EXPECT WIND SPEEDS TO DIMINISH

SUNDAY EVENING AS THE SYSTEM MOVES EASTWARD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WATCH MEANS THERE IS THE POTENTIAL FOR A HAZARDOUS

HIGH WIND EVENT...WITH SUSTAINED WINDS GREATER THAN 40 MPH...OR

GUSTS GREATER THAN 58 MPH. MONITOR THE LATEST FORECASTS AND

WARNINGS FOR UPDATES ON THIS SITUATION. ADDITIONAL WEATHER

INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

WWUS75 KFGZ 221047

NPWFGZ

URGENT - WEATHER MESSAGE

NATIONAL WEATHER SERVICE FLAGSTAFF AZ

347 AM MST SUN MAR 22 2009

AZZ010-011-016-017-039-221900-

/O.UPG.KFGZ.WI.Y.0005.090322T1600Z-090323T0600Z/

/O.NEW.KFGZ.HW.W.0001.090322T1600Z-090323T0600Z/

CHINLE VALLEY-CHUSKA MOUNTAINS AND DEFIANCE PLATEAUEASTERN MOGOLLON RIM-WHITE MOUNTAINS-BLACK MESA AREAINCLUDING THE CITIES OF...CANYON DE CHELLY...CHINLE...KAYENTA...

WINDOW ROCK...GANADO...HEBER...HAPPY JACK...FOREST LAKES...

SHOW LOW...GREER...PINETOP...NAVAJO N.M.

347 AM MST SUN MAR 22 2009

...HIGH WIND WARNING IN EFFECT FROM 9 AM THIS MORNING TO 11 PM

MST THIS EVENING...

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF HAS ISSUED A HIGH WIND

WARNING...WHICH IS IN EFFECT FROM 9 AM THIS MORNING TO 11 PM MST

THIS EVENING. THE WIND ADVISORY IS NO LONGER IN EFFECT.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN TODAY

WILL BRING STRONG WINDS TO NORTHERN ARIZONA. SOUTHWEST WINDS WILL

BEGIN TO INCREASE BY MID MORNING...REACHING SPEEDS OF 30 TO 40 MPH

WITH GUSTS FROM 55 TO 60 MPH BY EARLY AFTERNOON. THESE STRONG

WINDS ARE ANTICIPATED TO CONTINUE INTO THE LATE EVENING HOURS AS

THE STORM SYSTEM MOVES THROUGH THE AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED
127

OR OCCURRING...WITH SUSTAINED WIND SPEEDS GREATER THAN 40 MPH OR

GUSTS GREATER THAN 58 MPH. WINDS THIS STRONG CAN CAUSE PROPERTY

DAMAGE. CONTINUE TO MONITOR THE LATEST FORECASTS. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

AZZ012>014-040-221900-

/O.UPG.KFGZ.HW.A.0001.090322T1600Z-090323T0600Z/

/O.NEW.KFGZ.HW.W.0001.090322T1600Z-090323T0600Z/

LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTYLITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTYLITTLE COLORADO RIVER VALLEY IN APACHE COUNTYNORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-

INCLUDING THE CITIES OF...WUPATKI N.M....TUBA CITY...WINSLOW...

HOLBROOK...SNOWFLAKE...ST. JOHNS...SPRINGERVILLE...DILKON...

KYKOTSMOVI

347 AM MST SUN MAR 22 2009

...HIGH WIND WARNING IN EFFECT FROM 9 AM THIS MORNING TO 11 PM

MST THIS EVENING...

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF HAS ISSUED A HIGH WIND

WARNING...WHICH IS IN EFFECT FROM 9 AM THIS MORNING TO 11 PM MST

THIS EVENING. THE HIGH WIND WATCH IS NO LONGER IN EFFECT.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN TODAY WILL

BRING VERY STRONG WINDS MUCH OF THE REGION. SOUTHWEST WINDS WILL

BEGIN TO INCREASE THIS MORNING...REACHING SPEEDS OF 35 TO 45 MPH

WITH GUSTS UP TO 65 MPH OVER THE LITTLE COLORADO RIVER VALLEY AND

ADJACENT AREAS BY EARLY AFTERNOON. THESE STRONG WINDS ARE

ANTICIPATED TO CONTINUE INTO THE MID TO LATE EVENING HOURS AS THE

STORM SYSTEM MOVES THROUGH THE AREA. AREAS OF BLOWING DUST ARE

LIKELY AND MAY CAUSE LOCALLY REDUCED VISIBILITY ALONG AREA ROADS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED

OR OCCURRING...WITH SUSTAINED WIND SPEEDS GREATER THAN 40 MPH OR

GUSTS GREATER THAN 58 MPH. WINDS THIS STRONG CAN CAUSE PROPERTY

DAMAGE. CONTINUE TO MONITOR THE LATEST FORECASTS. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

AZZ004>009-015-018-037-038-221900-

/O.CON.KFGZ.WI.Y.0005.090322T1600Z-090323T0600Z/

KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRYCOCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINSNORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARDWESTERN MOGOLLON RIM-NORTHERN GILA COUNTYYAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONSINCLUDING THE CITIES OF...JACOB LAKE...FREDONIA...PAGE...

LEES FERRY...GRAND CANYON VILLAGE...SUPAI...NORTH RIM...VALLE...

PRESCOTT...SELIGMAN...ASH FORK...KEAMS CANYON...KAIBITO...

FLAGSTAFF...WILLIAMS...MUNDS PARK...PAYSON...STRAWBERRY...YOUNG...

COTTONWOOD...CAMP VERDE...CORDES JUNCTION...BAGDAD...SEDONA

347 AM MST SUN MAR 22 2009

...WIND ADVISORY REMAINS IN EFFECT FROM 9 AM THIS MORNING TO

11 PM MST THIS EVENING...

A WIND ADVISORY REMAINS IN EFFECT FROM 9 AM THIS MORNING TO 11 PM

MST THIS EVENING.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN TODAY WILL

BRING STRONG WINDS TO NORTHERN ARIZONA. SOUTHWEST WINDS WILL
128

BEGIN TO INCREASE THIS MORNING...REACHING SPEEDS OF 30 TO 40 MPH

WITH GUSTS FROM 45 TO 55 MPH BY EARLY AFTERNOON. THESE STRONG

WINDS ARE ANTICIPATED TO CONTINUE INTO THE LATE EVENING HOURS AS

THE STORM SYSTEM MOVES THROUGH THE AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WIND ADVISORY MEANS THAT SUSTAINED WINDS OF 30 TO 39 MPH...OR

GUSTS FROM 40 TO 57 MPH...ARE EXPECTED. WINDS THIS STRONG CAN

MAKE DRIVING DIFFICULT...ESPECIALLY FOR HIGH PROFILE VEHICLES.

CONSIDER SECURING LOOSE BELONGINGS ON YOUR PROPERTY. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

JJ

WWUS75 KFGZ 221837

NPWFGZ

URGENT - WEATHER MESSAGE

NATIONAL WEATHER SERVICE FLAGSTAFF AZ

1137 AM MST SUN MAR 22 2009

AZZ010>014-016-017-039-040-230400-

/O.CON.KFGZ.HW.W.0001.000000T0000Z-090323T0600Z/

CHINLE VALLEY-CHUSKA MOUNTAINS AND DEFIANCE PLATEAULITTLE COLORADO RIVER VALLEY IN COCONINO COUNTYLITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTYLITTLE COLORADO RIVER VALLEY IN APACHE COUNTYEASTERN MOGOLLON RIM-WHITE MOUNTAINS-BLACK MESA AREANORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-

INCLUDING THE CITIES OF...CANYON DE CHELLY...CHINLE...KAYENTA...

WINDOW ROCK...GANADO...WUPATKI N.M....TUBA CITY...WINSLOW...

HOLBROOK...SNOWFLAKE...ST. JOHNS...SPRINGERVILLE...HEBER...

HAPPY JACK...FOREST LAKES...SHOW LOW...GREER...PINETOP...

NAVAJO N.M....DILKON...KYKOTSMOVI

1137 AM MST SUN MAR 22 2009

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS

EVENING...

A HIGH WIND WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS

EVENING.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN TODAY

WILL BRING VERY STRONG WINDS TO MUCH OF THE REGION. SOUTHWEST

WINDS OF 20 TO 30 MPH HAVE DEVELOPED ACROSS LITTLE COLORADO RIVER

VALLEY AND ADJACENT AREAS AND WILL CONTINUE TO INCREASE

THROUGHOUT THE DAY...REACHING SPEEDS OF 35 TO 45 MPH WITH GUSTS UP

TO 65 MPH BY EARLY AFTERNOON. THESE STRONG WINDS ARE ANTICIPATED

TO CONTINUE INTO THE LATE EVENING HOURS AS THE STORM SYSTEM MOVES

THROUGH THE REGION. AREAS OF BLOWING DUST ARE LIKELY AND MAY CAUSE

LOCALLY REDUCED VISIBILITY ALONG AREA ROADS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED

OR OCCURRING...WITH SUSTAINED WIND SPEEDS GREATER THAN 40 MPH OR

GUSTS GREATER THAN 58 MPH. WINDS THIS STRONG CAN CAUSE PROPERTY

DAMAGE. CONTINUE TO MONITOR THE LATEST FORECASTS. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

AZZ004>009-015-018-037-038-230400-

/O.CON.KFGZ.WI.Y.0005.000000T0000Z-090323T0600Z/

KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRY-
129

COCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINSNORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARDWESTERN MOGOLLON RIM-NORTHERN GILA COUNTYYAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONSINCLUDING THE CITIES OF...JACOB LAKE...FREDONIA...PAGE...

LEES FERRY...GRAND CANYON VILLAGE...SUPAI...NORTH RIM...VALLE...

PRESCOTT...SELIGMAN...ASH FORK...KEAMS CANYON...KAIBITO...

FLAGSTAFF...WILLIAMS...MUNDS PARK...PAYSON...STRAWBERRY...YOUNG...

COTTONWOOD...CAMP VERDE...CORDES JUNCTION...BAGDAD...SEDONA

1137 AM MST SUN MAR 22 2009

...WIND ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST THIS EVENING...

A WIND ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST THIS EVENING.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN TODAY

WILL BRING STRONG WINDS TO NORTHERN ARIZONA. SOUTHWEST WINDS OF 15

TO 25 MPH HAVE DEVELOPED ACROSS MUCH OF THE ADVISORY AREA AND WILL

CONTINUE TO INCREASE THROUGHOUT THE DAY...REACHING SPEEDS OF 30 TO 40

MPH WITH GUSTS FROM 45 TO 55 MPH BY EARLY AFTERNOON. THESE STRONG

WINDS ARE ANTICIPATED TO CONTINUE INTO THE LATE EVENING HOURS AS

THE STORM SYSTEM MOVES THROUGH THE REGION.

THE FOLLOWING SITES HAVE VERIFIED ADVISORY CRITERIA...

GRAND CANYON AIRPORT ... 35 MPH SUSTAINED

FOUR SPRINGS RAWS ...... 43 MPH GUST

HOUSEROCK RAWS ......... 48 MPH GUST

GRAND CANYON AIRPORT ... 53 MPH GUST

FRAZIER WELLS RAWS ..... 41 MPH GUST

I-40 AT ASH FORK ....... 42 MPH GUST

HUMBUG CREEK RAWS ...... 40 MPH GUST

FLAGSTAFF AIRPORT ...... 41 MPH GUST

GREENBASE RAWS ......... 40 MPH GUST

WUPATKI RAWS ........... 42 MPH GUST

SHOW LOW AIRPORT ....... 43 MPH GUST

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WIND ADVISORY MEANS THAT SUSTAINED WINDS OF 30 TO 39 MPH...OR

GUSTS FROM 40 TO 57 MPH...ARE EXPECTED. WINDS THIS STRONG CAN

MAKE DRIVING DIFFICULT...ESPECIALLY FOR HIGH PROFILE VEHICLES.

CONSIDER SECURING LOOSE BELONGINGS ON YOUR PROPERTY. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

WWUS75 KFGZ 222137

NPWFGZ

URGENT - WEATHER MESSAGE

NATIONAL WEATHER SERVICE FLAGSTAFF AZ

237 PM MST SUN MAR 22 2009

AZZ006>009-015-230545-

/O.UPG.KFGZ.WI.Y.0005.000000T0000Z-090323T0600Z/

/O.EXA.KFGZ.HW.W.0001.000000T0000Z-090323T0600Z/

GRAND CANYON COUNTRY-COCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINSNORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARDWESTERN MOGOLLON RIMINCLUDING THE CITIES OF...GRAND CANYON VILLAGE...SUPAI...

NORTH RIM...VALLE...PRESCOTT...SELIGMAN...ASH FORK...

KEAMS CANYON...KAIBITO...FLAGSTAFF...WILLIAMS...MUNDS PARK

237 PM MST SUN MAR 22 2009

...HIGH WIND WARNING IN EFFECT UNTIL 11 PM MST THIS EVENING...

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF HAS ISSUED A HIGH WIND
130

WARNING...WHICH IS IN EFFECT UNTIL 11 PM MST THIS EVENING. THE

WIND ADVISORY IS NO LONGER IN EFFECT.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN WILL

BRING STRONG WINDS TO NORTHERN ARIZONA. SOUTHWEST WINDS OF 40 TO

50 MPH WITH GUSTS EXCEEDING 60 MPH HAVE DEVELOPED AND WILL

CONTINUE ACROSS THE WARNING AREA. THESE STRONG WINDS ARE

ANTICIPATED TO CONTINUE INTO THE LATE EVENING HOURS AS THE STORM

SYSTEM MOVES THROUGH THE REGION. AREAS OF BLOWING DUST ARE LIKELY

AND MAY CAUSE LOCALLY REDUCED VISIBILITY ALONG AREA ROADS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED

OR OCCURRING...WITH SUSTAINED WIND SPEEDS GREATER THAN 40 MPH OR

GUSTS GREATER THAN 58 MPH. WINDS THIS STRONG CAN CAUSE PROPERTY

DAMAGE. CONTINUE TO MONITOR THE LATEST FORECASTS. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

AZZ010>014-016-017-039-040-230545-

/O.CON.KFGZ.HW.W.0001.000000T0000Z-090323T0600Z/

CHINLE VALLEY-CHUSKA MOUNTAINS AND DEFIANCE PLATEAULITTLE COLORADO RIVER VALLEY IN COCONINO COUNTYLITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTYLITTLE COLORADO RIVER VALLEY IN APACHE COUNTYEASTERN MOGOLLON RIM-WHITE MOUNTAINS-BLACK MESA AREANORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-

INCLUDING THE CITIES OF...CANYON DE CHELLY...CHINLE...KAYENTA...

WINDOW ROCK...GANADO...WUPATKI N.M....TUBA CITY...WINSLOW...

HOLBROOK...SNOWFLAKE...ST. JOHNS...SPRINGERVILLE...HEBER...

HAPPY JACK...FOREST LAKES...SHOW LOW...GREER...PINETOP...

NAVAJO N.M....DILKON...KYKOTSMOVI

237 PM MST SUN MAR 22 2009

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS

EVENING...

A HIGH WIND WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS

EVENING.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN TODAY

WILL BRING VERY STRONG WINDS TO MUCH OF THE REGION. SOUTHWEST OF

35 TO 45 MPH WITH GUSTS UP TO 65 MPH HAVE DEVELOPED AND WILL CONTINUE

ACROSS THE LITTLE COLORADO RIVER VALLEY AND ADJACENT AREAS. THESE

STRONG WINDS ARE ANTICIPATED TO CONTINUE INTO THE LATE EVENING

HOURS AS THE STORM SYSTEM MOVES THROUGH THE REGION. AREAS OF

BLOWING DUST ARE LIKELY AND MAY CAUSE LOCALLY REDUCED VISIBILITY

ALONG AREA ROADS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED

OR OCCURRING...WITH SUSTAINED WIND SPEEDS GREATER THAN 40 MPH OR

GUSTS GREATER THAN 58 MPH. WINDS THIS STRONG CAN CAUSE PROPERTY

DAMAGE. CONTINUE TO MONITOR THE LATEST FORECASTS. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

AZZ004-005-018-037-038-230545-

/O.CON.KFGZ.WI.Y.0005.000000T0000Z-090323T0600Z/

KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-NORTHERN GILA COUNTYYAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONSINCLUDING THE CITIES OF...JACOB LAKE...FREDONIA...PAGE...

LEES FERRY...PAYSON...STRAWBERRY...YOUNG...COTTONWOOD...
131

CAMP VERDE...CORDES JUNCTION...BAGDAD...SEDONA

237 PM MST SUN MAR 22 2009

...WIND ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST THIS EVENING...

A WIND ADVISORY REMAINS IN EFFECT UNTIL 11 PM MST THIS EVENING.

A STRONG LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT BASIN WILL

BRING STRONG WINDS TO NORTHERN ARIZONA. SOUTHWEST WINDS OF 30 TO

40 MPH WITH GUSTS FROM 45 TO 55 MPH HAVE DEVELOPED AND WILL

CONTINUE ACROSS THE ADVISORY AREA. THESE STRONG WINDS ARE

ANTICIPATED TO CONTINUE INTO THE LATE EVENING HOURS AS THE STORM

SYSTEM MOVES THROUGH THE REGION.

THE FOLLOWING SITES HAVE VERIFIED ADVISORY CRITERIA...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WIND ADVISORY MEANS THAT SUSTAINED WINDS OF 30 TO 39 MPH...OR

GUSTS FROM 40 TO 57 MPH...ARE EXPECTED. WINDS THIS STRONG CAN

MAKE DRIVING DIFFICULT...ESPECIALLY FOR HIGH PROFILE VEHICLES.

CONSIDER SECURING LOOSE BELONGINGS ON YOUR PROPERTY. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$

AZZ011-013-014-017-040-230600-

/O.CON.KFGZ.HW.W.0001.000000T0000Z-090323T0600Z/

CHUSKA MOUNTAINS AND DEFIANCE PLATEAULITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTYLITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-WHITE MOUNTAINSNORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-

INCLUDING THE CITIES OF...WINDOW ROCK...GANADO...WINSLOW...

HOLBROOK...SNOWFLAKE...ST. JOHNS...SPRINGERVILLE...SHOW LOW...

GREER...PINETOP...DILKON...KYKOTSMOVI

940 PM MST SUN MAR 22 2009

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS

EVENING...

A HIGH WIND WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS

EVENING.

A STRONG AREA OF LOW PRESSURE MOVING ACROSS UTAH THIS EVENING WILL

BRING VERY STRONG WINDS PORTIONS OF EASTERN ARIZONA. SOUTHWEST

WINDS OF 35 TO 45 MPH WITH GUSTS UP TO 65 MPH WILL CONTINUE

ACROSS THE LITTLE COLORADO RIVER VALLEY AND ADJACENT AREAS. THESE

STRONG WINDS ARE ANTICIPATED TO CONTINUE SEVERAL MORE HOURS THIS

EVENING AS THE STORM SYSTEM PROGRESSES EASTWARD ACROSS THE REST

OF THE STATE...WITH THE STRONGEST WINDS MAINLY EAST OF A WINSLOW

TO WINDOW ROCK LINE. AREAS OF BLOWING DUST ARE LIKELY AND MAY

CAUSE LOCALLY REDUCED VISIBILITY ALONG AREA ROADS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED

OR OCCURRING...WITH SUSTAINED WIND SPEEDS GREATER THAN 40 MPH OR

GUSTS GREATER THAN 58 MPH. WINDS THIS STRONG CAN CAUSE PROPERTY

DAMAGE. CONTINUE TO MONITOR THE LATEST FORECASTS. ADDITIONAL

WEATHER INFORMATION IS ON THE WEB AT WWW.WEATHER.GOV/FLAGSTAFF.

&&

$$
132

 NWS SRRS PRODUCTS FOR:

 2009032112 to 2009032223

Grand Junction Colorado National Weather Service Forecast Office

WWUS75 KGJT 222143

NPWGJT

URGENT - WEATHER MESSAGE

NATIONAL WEATHER SERVICE GRAND JUNCTION CO

343 PM MDT SUN MAR 22 2009

...STRONG WINDS TO CONTINUE INTO EARLY THIS EVENING...

.AN APPROACHING VIGOROUS COLD FRONT HAS RESULTED IN STRONG WINDS

ACROSS EASTERN UTAH AND WESTERN COLORADO THAT WILL CONTINUE INTO

EARLY THIS EVENING. THE WINDS ARE EXPECTED TO DECREASE SOME IN

INTENSITY TOWARDS SUNSET.

COZ001-002-005>008-011-014-020>023-UTZ022-024-027-029-230100-

/O.NEW.KGJT.WI.Y.0002.090322T2143Z-090323T0100Z/

LOWER YAMPA RIVER BASIN-CENTRAL YAMPA RIVER BASINUPPER YAMPA RIVER BASIN-GRAND VALLEY-DEBEQUE TO SILT CORRIDORCENTRAL COLORADO RIVER BASINCENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASINUPPER GUNNISON RIVER VALLEY-PARADOX VALLEY/LOWER DOLORES RIVERFOUR CORNERS/UPPER DOLORES RIVER-ANIMAS RIVER BASINSAN JUAN RIVER BASIN-SOUTHEAST UTAH-EASTERN UINTA BASINARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGESINCLUDING THE CITIES OF...RANGELY...DINOSAUR...CRAIG...HAYDEN...

MEEKER...STEAMBOAT SPRINGS AND VICINITY...GRAND JUNCTION...

FRUITA...PALISADE...RIFLE...SILT...PARACHUTE...MESA...

GLENWOOD SPRINGS...EAGLE...CARBONDALE...CEDAREDGE...DELTA...

HOTCHKISS...MONTROSE...GUNNISON...CIMARRON...GATEWAY...NUCLA...

CORTEZ...DOVE CREEK...MANCOS...DURANGO...BAYFIELD...IGNACIO...

PAGOSA SPRINGS AND VICINITY...BLANDING...BLUFF...MEXICAN HAT...

VERNAL...JENSEN...BALLARD...FORT DUCHESNE...RANDLETT...MOAB...

CASTLE VALLEY...THOMPSON SPRINGS

343 PM MDT SUN MAR 22 2009

...WIND ADVISORY IN EFFECT UNTIL 7 PM MDT THIS EVENING...

THE NATIONAL WEATHER SERVICE IN GRAND JUNCTION HAS ISSUED A WIND

ADVISORY...WHICH IS IN EFFECT UNTIL 7 PM MDT THIS EVENING.

SUSTAINED SOUTHERLY WINDS OF 20 TO 30 MPH WITH GUSTS OF 45 TO 55

MPH WILL CONTINUE INTO EARLY THIS EVENING. BLOWING DUST IN MANY

AREAS WILL RESULT IN REDUCED VISIBILITIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PERSONS TRAVELING ACROSS EASTERN UTAH AND WESTERN COLORADO THROUGH

EARLY THIS EVENING SHOULD BE PREPARED TO ENCOUNTER REDUCED

VISIBILITIES IN BLOWING DUST. ADDITIONALLY...THE STRONG WINDS CAN

MAKE DRIVING DIFFICULT...ESPECIALLY FOR HIGH PROFILE VEHICLES ON

EAST-WEST ORIENTED HIGHWAYS.

&&

$$
133

 NWS SRRS PRODUCTS FOR:

 2009032112 to 2009032223

Albuquerque New Mexico National Weather Service Forecast Office

WWUS75 KABQ 221103

NPWABQ

URGENT - WEATHER MESSAGE

NATIONAL WEATHER SERVICE ALBUQUERQUE NM

503 AM MDT SUN MAR 22 2009

...SHARP UPTICK IN WINDS FOR MOST OF NORTH AND CENTRAL NEW MEXICO...

.AN UPPER LEVEL TROUGH WILL SWING ACROSS THE CENTRAL ROCKIES LATER

TODAY AND TONIGHT...INCREASING WINDS ALOFT AND INCREASING THE

SURFACE PRESSURE GRADIENT...BOTH OF WHICH WILL CAUSE WINDS TO

GREATLY INCREASE OVER MUCH OF THE WESTERN THREE QUARTERS OF NEW

MEXICO TODAY AND CONTINUE INTO TONIGHT ACROSS THE WEST HALF AND

INTO MONDAY ACROSS THE EAST HALF.

NMZ008-014-221800-

/O.NEW.KABQ.WI.Y.0017.090322T1800Z-090323T0600Z/

WEST CENTRAL MOUNTAINS-SOUTHWEST MOUNTAINS/UPPER GILA REGIONINCLUDING THE CITIES OF...GALLUP/GRANTS...GLENWOOD

503 AM MDT SUN MAR 22 2009

...WIND ADVISORY IN EFFECT FROM NOON TODAY TO MIDNIGHT MDT

TONIGHT...

THE NATIONAL WEATHER SERVICE IN ALBUQUERQUE HAS ISSUED A WIND

ADVISORY...WHICH IS IN EFFECT FROM NOON TODAY TO MIDNIGHT MDT

TONIGHT.

SOUTHWEST TO WEST WINDS WILL INCREASE RATHER QUICKLY TODAY WITH

SUSTAINED SPEEDS OF 25 TO NEARLY 40 MPH EXPECTED BY EARLY

AFTERNOON WITH OCCASIONAL GUSTS BETWEEN 45 AND 55 MPH IN SOME

LOCALES. AREAS OF BLOWING DUST ARE ALSO EXPECTED...WHICH WILL

REDUCE VISIBILITY AT TIMES. WINDS WILL GRADUALLY DIMINISH LATE

TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

&&

$$

NMZ009-015-221800-

/O.NEW.KABQ.WI.Y.0017.090322T2100Z-090323T0600Z/

MIDDLE RIO GRANDE VALLEY/ALBUQUERQUE METRO AREALOWER RIO GRANDE VALLEYINCLUDING THE CITIES OF...ALBUQUERQUE...SOCORRO

503 AM MDT SUN MAR 22 2009

...WIND ADVISORY IN EFFECT FROM 3 PM THIS AFTERNOON TO MIDNIGHT

MDT TONIGHT...

THE NATIONAL WEATHER SERVICE IN ALBUQUERQUE HAS ISSUED A WIND

ADVISORY...WHICH IS IN EFFECT FROM 3 PM THIS AFTERNOON TO

MIDNIGHT MDT TONIGHT.

SOUTHWEST TO WEST WINDS WILL INCREASE RATHER QUICKLY THIS

AFTERNOON WITH SUSTAINED SPEEDS INCREASING TO BETWEEN 25 AND 35

MPH DURING THE AFTERNOON WITH OCCASIONAL GUSTS UP TO 40 OR 45 MPH

IN SOME LOCALES. AREAS OF BLOWING DUST MAY ALSO BE KICKED

UP...WHICH WILL REDUCE VISIBILITY AT TIMES. WINDS WILL GRADUALLY

DIMINISH LATE TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...
134

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

&&

$$

NMZ004-005-010-011-016-017-026-221800-

/O.NEW.KABQ.WI.Y.0017.090322T2100Z-090324T0000Z/

SANGRE DE CRISTO MOUNTAINS-NORTHEAST HIGHLANDSSANDIA/MANZANO MOUNTAINS-CENTRAL HIGH PLAINS/ESTANCIA VALLEYLINCOLN COUNTY HIGH PLAINS/HONDO VALLEYCAPITAN/NORTHERN SACRAMENTO MOUNTAINSGUADALUPE MOUNTAINS OF CHAVES COUNTYINCLUDING THE CITIES OF...RED RIVER/TAOS/SANTA FE...

LAS VEGAS/RATON...SANDIA PARK/CEDAR CREST...MORIARTY/ESTANCIA...

CARRIZOZO...RUIDOSO

503 AM MDT SUN MAR 22 2009

...WIND ADVISORY IN EFFECT FROM 3 PM THIS AFTERNOON TO 6 PM MDT

MONDAY...

THE NATIONAL WEATHER SERVICE IN ALBUQUERQUE HAS ISSUED A WIND

ADVISORY...WHICH IS IN EFFECT FROM 3 PM THIS AFTERNOON TO 6 PM

MDT MONDAY.

SOUTHWEST TO WEST WINDS WILL INCREASE RATHER QUICKLY THIS AFTERNOON

WITH SUSTAINED SPEEDS REACHING 25 TO NEARLY 40 MPH DURING THE

AFTERNOON WITH OCCASIONAL GUSTS BETWEEN 45 AND 55 MPH IN SOME

LOCALES. AREAS OF BLOWING DUST MAY ALSO BE KICKED UP...WHICH WILL

REDUCE VISIBILITY AT TIMES. STRONG WINDS WILL LIKELY CONTINUE

TONIGHT AND THROUGH MONDAY AFTERNOON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

&&

$$

43

WWUS75 KABQ 221743

NPWABQ

URGENT - WEATHER MESSAGE

NATIONAL WEATHER SERVICE ALBUQUERQUE NM

1143 AM MDT SUN MAR 22 2009

...SHARP UPTICK IN WINDS FOR MOST OF NORTH AND CENTRAL NEW

MEXICO...

.AN UPPER LEVEL TROUGH WILL SWING ACROSS THE CENTRAL ROCKIES

THROUGH TONIGHT...INCREASING WINDS ALOFT AND INCREASING THE

SURFACE PRESSURE GRADIENT. THIS WILL CREATE STRONG WINDS OVER

MUCH OF THE WESTERN THREE QUARTERS OF NEW MEXICO THROUGH THIS

EVENING...AND CONTINUE ACROSS THE EASTERN HALF INTO MONDAY

AFTERNOON.

NMZ008-014-230000-

/O.UPG.KABQ.WI.Y.0017.090322T1800Z-090323T0600Z/

/O.NEW.KABQ.HW.W.0009.090322T1800Z-090323T0600Z/

WEST CENTRAL MOUNTAINS-SOUTHWEST MOUNTAINS/UPPER GILA REGIONINCLUDING THE CITIES OF...GALLUP/GRANTS...GLENWOOD

1143 AM MDT SUN MAR 22 2009

...HIGH WIND WARNING IN EFFECT UNTIL MIDNIGHT MDT TONIGHT...

THE NATIONAL WEATHER SERVICE IN ALBUQUERQUE HAS ISSUED A HIGH

WIND WARNING...WHICH IS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT. THE
135

WIND ADVISORY IS NO LONGER IN EFFECT.

SOUTHWEST WINDS WILL INCREASE THIS AFTERNOON TO 25 TO 35 MPH

WITH GUSTS UP TO 45 MPH BY EARLY AFTERNOON. WINDS WILL INCREASE

EVEN FURTHER BY LATE THIS AFTERNOON INTO EARLY THIS EVENING WITH

SUSTAINED SPEEDS OF 30 TO 40 MPH WITH GUSTS UP TO 60 MPH POSSIBLE.

AREAS OF BLOWING DUST ARE ALSO EXPECTED...WHICH WILL REDUCE

VISIBILITY AT TIMES. WINDS WILL GRADUALLY DIMINISH AFTER MIDNIGHT

TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A HIGH WIND WARNING MEANS HAZARDOUS WEATHER CONDITIONS

ARE IMMINENT OR HIGHLY LIKELY. VERY STRONG CROSS WINDS ARE LIKELY

ALONG INTERSTATE 40...ESPECIALLY BETWEEN GALLUP AND GRANTS.

&&

$$

NMZ017-230000-

/O.NEW.KABQ.HW.W.0009.090322T2100Z-090323T0600Z/

/O.EXT.KABQ.WI.Y.0017.090323T0600Z-090324T0000Z/

CAPITAN/NORTHERN SACRAMENTO MOUNTAINSINCLUDING THE CITY OF...RUIDOSO

1143 AM MDT SUN MAR 22 2009

...HIGH WIND WARNING IN EFFECT FROM 3 PM THIS AFTERNOON TO

MIDNIGHT MDT TONIGHT...

...WIND ADVISORY NOW IN EFFECT FROM MIDNIGHT TONIGHT TO 6 PM MDT

MONDAY...

THE NATIONAL WEATHER SERVICE IN ALBUQUERQUE HAS ISSUED A HIGH

WIND WARNING...WHICH IS IN EFFECT FROM 3 PM THIS AFTERNOON TO

MIDNIGHT MDT TONIGHT. THE WIND ADVISORY IS NOW IN EFFECT FROM

MIDNIGHT TONIGHT TO 6 PM MDT MONDAY.

SOUTHWEST WILL INCREASE RATHER QUICKLY THIS AFTERNOON TO 30 TO

40 MPH WITH GUSTS UP TO 60 MPH POSSIBLE IN SOME LOCALES. WINDS

WILL THEN TURN MORE WESTERLY AND DIMINISH TO 25 TO 35 MPH WITH

GUSTS UP TO 45 MPH AFTER MIDNIGHT THROUGH MONDAY AFTERNOON. AREAS

OF BLOWING DUST ARE ALSO POSSIBLE...WHICH WILL REDUCE VISIBILITY

AT TIMES. THE STRONGEST WINDS ARE EXPECTED BETWEEN LATE THIS

AFTERNOON AND MIDNIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

REMEMBER...A HIGH WIND WARNING MEANS HAZARDOUS WEATHER CONDITIONS

ARE IMMINENT OR HIGHLY LIKELY.

&&

$$

NMZ001-230000-

/O.EXB.KABQ.WI.Y.0017.090322T1800Z-090323T0600Z/

NORTHWEST PLATEAUINCLUDING THE CITY OF...FARMINGTON

1143 AM MDT SUN MAR 22 2009

...WIND ADVISORY IN EFFECT UNTIL MIDNIGHT MDT TONIGHT...

THE NATIONAL WEATHER SERVICE IN ALBUQUERQUE HAS ISSUED A WIND

ADVISORY...WHICH IS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT.

SOUTHWEST WINDS WILL INCREASE RATHER QUICKLY THIS AFTERNOON TO

25 TO 35 MPH WITH GUSTS UP TO 45 MPH IN SOME LOCALES. THE STRONGEST

WINDS ARE EXPECTED ALONG THE HIGHWAY 491 CORRIDOR BETWEEN NASCHITTI

AND SHIPROCK. AREAS OF BLOWING DUST ARE ALSO POSSIBLE...WHICH WILL

REDUCE VISIBILITY AT TIMES. WINDS WILL GRADUALLY DIMINISH LATE TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...
136

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

&&

$$

NMZ009-015-230000-

/O.CON.KABQ.WI.Y.0017.090322T2100Z-090323T0600Z/

MIDDLE RIO GRANDE VALLEY/ALBUQUERQUE METRO AREALOWER RIO GRANDE VALLEYINCLUDING THE CITIES OF...ALBUQUERQUE...SOCORRO

1143 AM MDT SUN MAR 22 2009

...WIND ADVISORY REMAINS IN EFFECT FROM 3 PM THIS AFTERNOON TO

MIDNIGHT MDT TONIGHT...

A WIND ADVISORY REMAINS IN EFFECT FROM 3 PM THIS AFTERNOON TO

MIDNIGHT MDT TONIGHT.

SOUTHWEST WINDS WILL INCREASE RATHER QUICKLY THIS AFTERNOON TO

25 TO 35 MPH WITH GUSTS UP TO 45 MPH IN SOME LOCALES. AREAS OF

BLOWING DUST ARE ALSO POSSIBLE...WHICH WILL REDUCE VISIBILITY

AT TIMES. WINDS WILL GRADUALLY DIMINISH LATE TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

&&

$$

NMZ004-005-010-011-016-026-230000-

/O.CON.KABQ.WI.Y.0017.090322T2100Z-090324T0000Z/

SANGRE DE CRISTO MOUNTAINS-NORTHEAST HIGHLANDSSANDIA/MANZANO MOUNTAINS-CENTRAL HIGH PLAINS/ESTANCIA VALLEYLINCOLN COUNTY HIGH PLAINS/HONDO VALLEYGUADALUPE MOUNTAINS OF CHAVES COUNTYINCLUDING THE CITIES OF...RED RIVER/TAOS/SANTA FE...

LAS VEGAS/RATON...SANDIA PARK/CEDAR CREST...MORIARTY/ESTANCIA...

CARRIZOZO

1143 AM MDT SUN MAR 22 2009

...WIND ADVISORY REMAINS IN EFFECT FROM 3 PM THIS AFTERNOON TO

6 PM MDT MONDAY...

A WIND ADVISORY REMAINS IN EFFECT FROM 3 PM THIS AFTERNOON TO

6 PM MDT MONDAY.

SOUTHWEST TO WEST WINDS WILL CONTINUE INCREASING THIS AFTERNOON

WITH SUSTAINED SPEEDS OF 25 TO NEARLY 40 MPH WITH OCCASIONAL GUSTS

BETWEEN 45 AND 55 MPH IN SOME LOCALES. AREAS OF BLOWING DUST ARE

ALSO POSSIBLE... WHICH WILL REDUCE VISIBILITY AT TIMES. STRONG

WINDS WILL LIKELY CONTINUE TONIGHT AND THROUGH MONDAY AFTERNOON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

&&

$$

WWUS75 KABQ 222353

NPWABQ

URGENT - WEATHER MESSAGE

NATIONAL WEATHER SERVICE ALBUQUERQUE NM

553 PM MDT SUN MAR 22 2009

...STRONG WINDS CONTINUE ACROSS PORTIONS OF NEW MEXICO...
137

.AN UPPER LEVEL TROUGH WILL SWING ACROSS THE CENTRAL ROCKIES

TONIGHT...INCREASING WINDS ALOFT AS WELL AS INCREASING THE

SURFACE PRESSURE GRADIENT. THIS WILL CREATE STRONG WINDS OVER MUCH

OF CENTRAL AND WESTERN NEW MEXICO THROUGH AT LEAST MIDNIGHT. THE

STRONGEST WINDS WILL THEN SHIFT TO AREAS ALONG AND EAST OF THE

CENTRAL MOUNTAIN CHAIN ON MONDAY.

NMZ017-230600-

/O.CON.KABQ.HW.W.0009.000000T0000Z-090323T0600Z/

/O.CON.KABQ.WI.Y.0017.090323T0600Z-090324T0000Z/

CAPITAN/NORTHERN SACRAMENTO MOUNTAINSINCLUDING THE CITY OF...RUIDOSO

553 PM MDT SUN MAR 22 2009

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL MIDNIGHT MDT

TONIGHT...

...WIND ADVISORY REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 6 PM

MDT MONDAY...

A HIGH WIND WARNING REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT.

A WIND ADVISORY REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 6 PM

MDT MONDAY.

SOUTHWEST WINDS OF 30 TO 40 MPH WITH GUSTS UP TO 60 MPH WILL

CONTINUE THROUGH THE EVENING HOURS ACROSS THE NORTHERN SACRAMENTO

MOUNTAINS. WINDS WILL BECOME MORE WESTERLY AND DIMINISH TO 25

TO 35 MPH WITH GUSTS UP TO 45 MPH AFTER MIDNIGHT THROUGH MONDAY

AFTERNOON. AREAS OF BLOWING DUST ARE ALSO POSSIBLE...WHICH WILL

REDUCE VISIBILITY AT TIMES. THE STRONGEST WINDS ARE EXPECTED

THROUGH MIDNIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A HIGH WIND WARNING MEANS HAZARDOUS WEATHER CONDITIONS

ARE IMMINENT OR HIGHLY LIKELY.

&&

$$

NMZ008-014-230600-

/O.CON.KABQ.HW.W.0009.000000T0000Z-090323T0600Z/

WEST CENTRAL MOUNTAINS-SOUTHWEST MOUNTAINS/UPPER GILA REGIONINCLUDING THE CITIES OF...GALLUP/GRANTS...GLENWOOD

553 PM MDT SUN MAR 22 2009

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL MIDNIGHT MDT

TONIGHT...

A HIGH WIND WARNING REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT.

SOUTHWEST WINDS OF 35 TO 45 MPH WITH GUSTS UP TO 60 MPH WILL

CONTINUE ACROSS THE WEST CENTRAL AND SOUTHWEST MOUNTAINS THROUGH

MIDNIGHT. AREAS OF BLOWING DUST ARE ALSO EXPECTED...WHICH WILL

REDUCE VISIBILITY AT TIMES. WINDS WILL GRADUALLY DIMINISH AFTER

MIDNIGHT TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A HIGH WIND WARNING MEANS HAZARDOUS WEATHER CONDITIONS

ARE IMMINENT OR HIGHLY LIKELY. VERY STRONG CROSS WINDS ARE LIKELY

ALONG INTERSTATE 40...ESPECIALLY BETWEEN GALLUP AND GRANTS.

&&

$$

NMZ009-015-230600-

/O.CON.KABQ.WI.Y.0017.000000T0000Z-090323T0600Z/

MIDDLE RIO GRANDE VALLEY/ALBUQUERQUE METRO AREALOWER RIO GRANDE VALLEYINCLUDING THE CITIES OF...ALBUQUERQUE...SOCORRO

553 PM MDT SUN MAR 22 2009

...WIND ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT...
138

A WIND ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT.

SOUTHWEST WINDS OF 25 TO 35 MPH WITH GUSTS UP TO 45 MPH WILL

CONTINUE ACROSS THE MIDDLE AND LOWER RIO GRANDE VALLEY THROUGH THE

EVENING HOURS. AREAS OF BLOWING DUST ARE ALSO POSSIBLE...WHICH WILL

REDUCE VISIBILITY AT TIMES. WINDS WILL GRADUALLY DIMINISH LATE

TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

&&

$$

NMZ004-005-010-011-016-026-230600-

/O.CON.KABQ.WI.Y.0017.000000T0000Z-090324T0000Z/

SANGRE DE CRISTO MOUNTAINS-NORTHEAST HIGHLANDSSANDIA/MANZANO MOUNTAINS-CENTRAL HIGH PLAINS/ESTANCIA VALLEYLINCOLN COUNTY HIGH PLAINS/HONDO VALLEYGUADALUPE MOUNTAINS OF CHAVES COUNTYINCLUDING THE CITIES OF...RED RIVER/TAOS/SANTA FE...

LAS VEGAS/RATON...SANDIA PARK/CEDAR CREST...MORIARTY/ESTANCIA...

CARRIZOZO

553 PM MDT SUN MAR 22 2009

...WIND ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT MONDAY...

A WIND ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT MONDAY.

SOUTHWEST TO WEST WINDS WILL CONTINUE TONIGHT THROUGH MONDAY WITH

SUSTAINED SPEEDS OF 25 TO 35 MPH WITH OCCASIONAL GUSTS BETWEEN 45

AND 55 MPH. AREAS OF BLOWING DUST ARE ALSO POSSIBLE... WHICH WILL

REDUCE VISIBILITY AT TIMES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

&&

$$

NMZ001-230600-

/O.CON.KABQ.WI.Y.0017.000000T0000Z-090323T0600Z/

NORTHWEST PLATEAUINCLUDING THE CITY OF...FARMINGTON

553 PM MDT SUN MAR 22 2009

...WIND ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT...

A WIND ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT.

SOUTHWEST WINDS OF 25 TO 35 MPH WITH GUSTS UP TO 45 MPH WILL

CONTINUE ACROSS THE NORTHWEST PLATEAU. THE STRONGEST WINDS ARE

EXPECTED ALONG THE HIGHWAY 491 CORRIDOR BETWEEN NASCHITTI AND

SHIPROCK. AREAS OF BLOWING DUST ARE ALSO POSSIBLE...WHICH WILL

REDUCE VISIBILITY AT TIMES. WINDS WILL GRADUALLY DIMINISH LATE

TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOTORISTS SHOULD EXERCISE CAUTION WHILE DRIVING IN THE WIND

ADVISORY AREA. SUDDEN GUSTS OF WIND MAY CAUSE YOU TO LOSE CONTROL

OF YOUR VEHICLE. EXTRA ATTENTION SHOULD BE GIVEN TO CROSS WINDS.

&&

$$

34