Wildfire Smoke Update
for
Thursday, September 20, 2012 3:28 PM

Satellite Photos | Locations and Smoke Conditions

Today's Report and Forecast	Today's Summary
Atmospheric conditions have been very much the same for the last couple of days under a ridge of high pressure. Dispersion conditions are typically very poor under a ridge of high pressure, and our current air quality verifies that fact. The atmosphere is very stable and stagnant, and under such conditions, pollution like wildfire smoke cannot mix and blow away in the air. The air has been quite still across western Montana, and smoke has just been accumulating day after day. Air quality is poor over a much larger region today because of the build-up of wildfire smoke. Frenchtown, Missoula, and Hamilton are VERY UNHEALTHY. These valleys are the closest to the largest fires and most dense smoke. Moving away from these valleys, air quality is UNHEALTHY in Helena, Butte, Bozeman, Dillon, and West Yellowstone. Locations in the entire southwest region is likely UNHEALTHY as well. In Seeley Lake and up the Swan Valley, cumulative particulate concentrations are UNHEALTHY FOR SENSITIVE GROUPS. Libby and some of the other, smaller valleys of far northwestern Montana are also UNHEALTHY FOR SENSITIVE GROUPS. Cumulative particulate concentrations in the Flathead Valley have recently become MODERATE. Cumulative particulate concentrations also remain MODERATE in Great Falls. Most of eastern Montana is GOOD this afternoon. The stable ridge of high pressure will persist at least through the weekend. Poor dispersion will keep air quality generally the same, if not a little worse across the southwest where smoke concentrations are the highest. 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. However, smoke will stay across the region. 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 which would, at the very least, reduce the strength of the ridge to improve dispersion conditions and help to get some of the smoke out of here.	Frenchtown, Missoula, and Hamilton are VERY UNHEALTHY. These valleys are the closest to the largest fires and most dense smoke. Moving away from these valleys, air quality is UNHEALTHY in Helena, Butte, Bozeman, Dillon, and West Yellowstone. Locations in the entire southwest region is likely UNHEALTHY as well. In Seeley Lake and up the Swan Valley, cumulative particulate concentrations are UNHEALTHY FOR SENSITIVE GROUPS. Libby and some of the other, smaller valleys of far northwestern Montana are also UNHEALTHY FOR SENSITIVE GROUPS. Cumulative particulate concentrations in the Flathead Valley have recently become MODERATE. Cumulative particulate concentrations also remain MODERATE in Great Falls. Most of eastern Montana is GOOD this afternoon.
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 2:15 this afternoon. Some high and thin clouds are across eastern Montana. Smoke is easily visible in the valleys of eastern Idaho, and even a very dense upper-air smoke plume in southwestern Idaho. Because the smoke across Montana is mostly near the ground and in the valleys, it is almost impossible to see it in this black and white image.  




 
This is a high-definition, and colored satellite image of eastern Idaho/western Montana from noon today. Some is a little more noticeable in our valleys in the colored image. The Missoula and Bitterroot Valleys have a much grayer appearance than some of the other valleys, for example.


If you are having trouble getting your bearings straight: the Flathead Lake is near the top-center of the image. The very smoky/gray lines in the center of the image are Idaho’s valleys, and just to the right is the Bitterroot. Canyon Ferry Lake is also visible on the right side of the image, near the center.

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 

This webcam is at the Whitefish Ski Resort and looks south across the Flathead Valley. The white along the horizon is the smoke that has settled into the Flathead Valley.

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.