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Wildfire Smoke Update
for
Tuesday, May 7, 2013 2:15 PM

Satellite Photos | Locations and Smoke Conditions


Today's Report and Forecast Today's Summary
We saw an early-season smoke event in the Helena Valley, Great Falls, and off the Rocky Mountain Front this afternoon. Specifically in Helena, the smoke started to roll through shortly before 11:00 AM and visibility dropped to around 10 miles. There was a small spike in the observed PM2.5 at the air monitor in the middle of the valley, but all hourly concentrations remained GOOD. Likewise in Great Falls, a spike in the PM2.5 was observed in the late morning and visibility was also reduced as the smoke rolled through there.

The smoke that we see today is actually leftover from prescribed and agricultural burns all the way into Canada from yesterday. The NOAA Satellite image below shows the number of large fires (red dots) in Alberta and Saskatchewan. A few of these fires produced quite a bit of smoke, as indicated by the green and yellow plumes. Throughout the morning, a weak cold front moved south into Montana, carrying with it the air that contained all of that smoke. It seems that the thickest smoke was right along the frontal boundary, which is why the air got so smoky, so quickly. The smoke in the Helena Valley was not caused by any residential or prescribed burns nearby, given the north winds and the fact that locations to our north (like Great Falls, Choteau, etc.) were smoky as well.

The smoke seemed to be the strongest at the initial push of the cold front, and webcam images to our north support this idea, as the visibility has slightly improved there. This will not be a long-duration smoke event and the cumulative air quality in the Helena Valley (as averaged over 24 hours) should not reach levels that are UNHEALTHY FOR SENSITIVE GROUPS. The forecast for the rest of the week, starting tomorrow, is for increased instability and more westerly/northwesterly winds—simply put, good dispersion and winds that will help to move the smoke out of our area. Long-range visibility may remain slightly hazy, but the air quality should remain GOOD in all locations throughout the week ahead of a weather system on Friday/Saturday.
Locations off the Rocky Mountain Front, including Great Falls and the Helena Valley, saw quite a bit of smoke today. This smoke was actually left over from prescribed and agricultural burns in Canada yesterday, and a weak cold front brought it through west-central Montana today. The worst of the smoke was along the frontal boundary and conditions are already improving. Despite the reduced visibility and clearly visible smoke in the air, observed air quality has remained GOOD in Helena and Great Falls. This will be a short-duration smoke event, lasting mostly through the evening. Some haze may continue to reduce long-range visibility on Wednesday, but the weather will gradually become more active and unstable throughout the rest of the week, which will work to get rid of this smoke.
Residents near active fires and under plumes aloft need to remain aware of current conditions and use the visibility guidelines to guide their activity decisions as the situation changes.

Kristen Martin
State Air Quality Meteorologist
Air Resource Management Bureau
Montana Department of Environmental Quality
Phone: (406) 444-0283
Email: kmartin@mt.gov




This is the visible satellite image centered over Great Falls from 12:30 this afternoon. The smoke that we can see at the ground is not visible in these satellite images. Despite the reduced visibility today, the smoke is fairly evenly distributed or dispersed from the surface and up to several thousand feet in the air. 

This is the visible satellite image centered over Great Falls from 12:30 this afternoon. The smoke that we can see at the ground is not visible in these satellite images. Despite the reduced visibility today, the smoke is fairly evenly distributed or dispersed from the surface and up to several thousand feet in the air.


 
This image comes from NOAA’s satellite services division which shows the active fires and smoke plumes. This image corresponds to fire and smoke information from yesterday, May 6. You can see many fires across Alberta and Saskatchewan, as well as many smoke plumes. This is believed to be the source of the smoke that many of us experienced today across west-central Montana.

This image comes from NOAA’s satellite services division which shows the active fires and smoke plumes. This image corresponds to fire and smoke information from yesterday, May 6. You can see many fires across Alberta and Saskatchewan, as well as many smoke plumes. This is believed to be the source of the smoke that many of us experienced today across west-central Montana.
Red indicates hot spot detected. Green represents thin smoke, yellow is moderate smoke, and pink is dense smoke. Fire size is exaggerated for visibility at this scale.

The image below shows weather and atmospheric conditions across Montana this afternoon. The heavy blue line and blue arrows show the cold front that pushed south across parts of Montana today, as well as the source of the air. Again, based on our north winds, we can see that the source of the air behind the cold front is Alberta and Saskatchewan.

The image below shows weather and atmospheric conditions across Montana this afternoon. The heavy blue line and blue arrows show the cold front that pushed south across parts of Montana today, as well as the source of the air. Again, based on our north winds, we can see that the source of the air behind the cold front is Alberta and Saskatchewan.

Red indicates hot spot detected. Grey represents smoke seen by satellite. Fire size is exaggerated for visibility at this scale. To identify individual fires on graphic above go here: http://activefiremaps.fs.fed.us/lg_fire2.php 

This is the webcam image from Great Falls shortly after noon today. On a clear day, you should see the Rocky Mountain Front along the horizon. However, due to the smoke even here, the mountains are not visible and you can instead see the smoky haze in the air.

This is the webcam image from Great Falls shortly after noon today. On a clear day, you should see the Rocky Mountain Front along the horizon. However, due to the smoke even here, the mountains are not visible and you can instead see the smoky haze in the air.

The smoke report below compares particulate levels where information is available to MDEQ’s Health Effects Categories. Real time particulate information is currently available in most of the larger urban areas from several different sources including: DEQ run PM-10 BAMS and PM2.5 BAMS, NWS ASOS visibility monitors, and USFS remote access Nephelometers and BAMS. These advisories represent conditions between midnight and 8 AM and may change substantially throughout the day.

Locations and severity of forest fire smoke reports since midnight of the date above at reporting stations.
Health Effects Categories City
  Hazardous  
  Very Unhealthy  
  Unhealthy  
  Unhealthy for Sensitive Groups  
  Moderate

  

  Good

 All reporting locations 

B1(x) One-hour BAM value (number of values)
B8(x) Eight-hour average BAM
B24 24 hour  average BAM value
Vis(x) Visibility value (number of hours)
Vis(am/pm) Visibility value from twice/day reporting stations

Local impacts in areas immediately adjacent to active fires are expected to exceed some or all of the advisory levels.  DEQ recommends the use of local visibility guidelines to evaluate possible health risks and make informed activity decisions.