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Wildfire Smoke Update
for
Monday, September 24, 2012 8:45 AM

Satellite Photos | Locations and Smoke Conditions


Today's Report and Forecast Today's Summary
After a brief break from the wildfire smoke in the western valleys, the smoke settled back in last night and air quality is poor again. Cumulative particulate concentrations are HAZARDOUS in Hamilton and the Bitterroot Valley, and hourly concentrations are UNHEALTHY. Cumulative concentrations in Missoula, Frenchtown, and Seeley Lake are UNHEALTHY, but hourly concentrations are UNHEALTHY FOR SENSITIVE GROUPS and MODERATE, with an upward trend. Cumulative concentrations in the Flathead Valley are UNHEALTHY FOR SENSITIVE GROUPS, but hourly concentrations are GOOD. Other locations have had enough GOOD observations that we can say that the air quality is GOOD in Helena, Butte, Bozeman, West Yellowstone, Dillon, and most of eastern Montana.

The presence of clouds and the changing locations of smoke impacts are from a low pressure system that is making its way through parts of the western US. For the last week, we have been under a large, stable ridge of high pressure, and we saw mostly calm winds, clear skies, and heavy smoke because of it. That ridge is still over us, but this low pressure system is slowly cutting its way through the ridge. This morning, it is near the Oregon/Idaho/Nevada border. Its proximity to western Montana will continue to have an effect on our winds, which in turns affects our smoke impacts. Atmospheric winds are fairly variable in direction over western Montana, and will change throughout the day. In general, winds should generally blow from the east and southeast this afternoon, so smoke impacts will remain heaviest west of the Divide.

There will be another update this afternoon with the latest wildfire activity, smoke conditions, and a full forecast.
Please see "Today's Report and Forecast" (left). There will be another update this afternoon with the latest wildfire activity, smoke conditions, and a full forecast.
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




 




 








 




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

Today's particulate report below compares particulate levels received from DEQ's
reporting stations with MTDEQ’s Health Effect Categories.

Locations and severity of PM 2.5 particulate values over the past 24 hours from the time above.
Health Effects Categories City
  Hazardous  Hamilton B24
  Very Unhealthy  
  Unhealthy  Missoula B24
Frenchtown B24
Seeley Lake B24
  Unhealthy for Sensitive Groups  Flathead Valley B24
  Moderate

 Libby B24
Butte B24
Bozeman B24
West Yellowstone B24
-All hourly concentrations are GOOD-
 

  Good

 Great Falls
Helena
Billings
Sidney
Dillon
 

B1(x) One-hour BAM value (number of values)
B8(x) Eight-hour average BAM
B24 24 hour  average BAM value
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.