Wildfire Smoke Update
for
Friday, September 21, 2012 3:34 PM

Satellite Photos | Locations and Smoke Conditions

Today's Report and Forecast	Today's Summary
Air quality is still poor across western Montana this afternoon. Hourly particulate concentrations have been UNHEALTHY in Hamilton, and cumulative exposures should become HAZARDOUS in the next couple of hours. Cumulative smoke exposures are UNHEALTHY in Missoula, Frenchtown, Seeley Lake, Helena, Bozeman, and West Yellowstone. Hourly concentrations are UNHEALTHY FOR SENSITIVE GROUPS to UNHEALTHY in Missoula, and MODERATE to UNHEALTHY FOR SENSITIVE GROUPS in Frenchtown, Seeley Lake (and the Swan Valley), Helena, Bozeman, and West Yellowstone. Cumulative air quality is also UNHEALTHY FOR SENSITIVE GROUPS in Dillon, Butte, the Flathead Valley, and Great Falls, though hourly concentrations are generally GOOD to MODERATE, with some hours that are UNHEALTHY FOR SENSITIVE GROUPS. Cumulative particulate concentrations are MODERATE in Libby and most of eastern Montana is GOOD. A large area of heavy smoke is in the atmosphere over Idaho. Although dispersion is very poor and the winds, even tens of thousands of feet in the air are very light, some of this smoke may get pushed into southwestern Montana or sink in overnight. The stable ridge of high pressure will persist at least through the weekend. Poor dispersion will keep air quality generally the same, with varying periods of improvement and worsening. Over the weekend, a small weather system will move east from the west coast, and will move through the middle of this high pressure ridge which is over the western United States. This little weather system will stay south of Montana, but it will cause our atmospheric winds to become variable in direction through Monday. Smoke will stay across the region as dispersion continues to be poor. Once the little weather system moves east, the high pressure ridge will still be in place for the beginning of the week. Weather conditions will remain warm and dry with poor dispersion. Though the forecast may change, it looks as though some sort of weather system will move across the northwestern US in the middle of the week which could help clear the smoke.	Hourly particulate concentrations have been UNHEALTHY in Hamilton, and cumulative exposures should become HAZARDOUS in the next couple of hours. Cumulative smoke exposures are UNHEALTHY in Missoula, Frenchtown, Seeley Lake, Helena, Bozeman, and West Yellowstone. Hourly concentrations are UNHEALTHY FOR SENSITIVE GROUPS to UNHEALTHY in Missoula, and MODERATE to UNHEALTHY FOR SENSITIVE GROUPS in Frenchtown, Seeley Lake (and the Swan Valley), Helena, Bozeman, and West Yellowstone. Cumulative air quality is also UNHEALTHY FOR SENSITIVE GROUPS in Dillon, Butte, the Flathead Valley, and Great Falls, though hourly concentrations are generally GOOD to MODERATE, with some hours that are UNHEALTHY FOR SENSITIVE GROUPS. Cumulative particulate concentrations are MODERATE in Libby and most of eastern Montana is GOOD.
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.
Air Quality Bureau Montana Department of Environmental Quality Phone: (406) 444-3490 Email: DEQMTSmoke@mt.gov

This is the visible satellite image from 1:30 this afternoon. Skies are completely clear across the region thanks to the strong ridge of high pressure. Heavy smoke is saturated in the atmosphere over Idaho, as you can see a lighter gray over Idaho, instead of the darker gray over Montana and Wyoming.  




 
These are high-definition, colored satellite images of eastern Idaho and western Montana. The image to the left is from today, September 21, 2012. The image on the right is September 21, 2011. Notice the heavy amounts of smoke in today’s image compared to what it should be like. Last year’s image is completely clear, with only some high clouds in the Idaho panhandle.




This morning’s analysis from NOAA’s satellite services division shows the active fires in Montana and the smoke plumes combining and spreading downwind (the analyzed smoke is based on yesterday’s satellite coverage, the fire detects are based on last nights satellite coverage).


Red indicates hot spot detected. Green represents thin smoke, yellow is moderate smoke, and purple is dense smoke. 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 

Real time particulate information is currently available in most of the larger urban areas from MTDEQ's Today's Air website.

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.