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Wildfire Smoke Update
for
Tuesday, September 4, 2012 4:00 PM

Satellite Photos | Locations and Smoke Conditions


Today's Report and Forecast Today's Summary
A cold front is currently moving across eastern Montana, and winds have been very gusty because of it. Ahead of the cold front, relative humidities have also been very low. The combination of the strong winds, low humidities, and a change in wind direction with the cold front have kept the Red Flag Warnings in effect for eastern Montana through tonight. This cold front is part of a larger-scale weather system which is both helping to create good dispersion conditions, as well as changing the direction of high atmospheric winds. Those winds are coming mostly out of the northwest across all of western Montana and Idaho, so the smoke is taking a slightly different path this afternoon. Smoke from Idaho is blowing mostly to the southeast, so locations that have been near that smoke/no smoke border as of late are very clear this afternoon. Visibility has greatly improved in Missoula and Helena as the air is now GOOD there. However, the Bitterroot Valley, Beaverhead County, and Madison County are all still taking the brunt of the smoke, and this will continue into the evening. Cumulative smoke exposures in Hamilton are still UNHEALTHY, although hourly concentrations have just been MODERATE for the past few hours. This will likely go up as the evening continues on and more smoke is produced. Butte and Bozeman are also being affected by these fires, as well as fires nearby in Montana. Cumulative air quality in Butte is UNHEALTHY, but hourly concentrations have dropped to GOOD for the past three hours, and visibility has also improved there. Cumulative air quality in Bozeman is also UNHEALTHY, but like Butte, hourly concentrations have just fallen to GOOD in the past hour. Smoke is still visible in the air but visibility has improved since this morning. The newest location with smoke impacts has been West Yellowstone, where hourly particulate concentrations have become MODERATE for the past few hours. Finally, the Livingston area is still very smoky and is at least UNHEALTHY FOR SENSITIVE GROUPS. Everywhere else in Montana—northwest, central, the hi-line, and southeast—are all GOOD.

By this evening, air quality may get worse as those smoke plumes in Idaho continue to grow and spread to the east and southeast. Areas south of a line from Missoula to Helena should see an increase in smoke tonight and a decrease in air quality. This will last through the morning as inversions develop tonight and trap the smoke in the valleys and near the ground. Weather conditions will be mostly sunny and dry tomorrow, though cooler temperatures and higher humidities will help to keep the smoke and fires from becoming overly active like we have seen lately. Atmospheric winds will blow from the northwest tomorrow morning, but turning more westerly by the evening when smoke production will be the highest. A weather system and cold front will pass over Montana late tomorrow night and through the morning, bringing more strong winds. Thursday is also the one day where we have a chance for rain. The highest rain and thunderstorm chances will be along the northern Rocky Mountain Front and parts of the plains of central and northern Montana. Precipitation will be light, but any rain is welcomed. Temperatures will be very cool on Thursday thanks to the cold front, and atmospheric winds will change direction again. By the evening most of the winds will come out of the north and northwest, so Thursday and Thursday night may be the clearest that southwestern Montana has been for a few weeks! Air quality should be mostly GOOD by Thursday night and even into Friday for most of the state. Though Friday should be clear for most of the day, a ridge of high pressure will start to build in, which will start a warming trend over the weekend. By Saturday and Sunday, atmospheric winds will be such that smoke will start to blow back into southwestern Montana and east into the plains.
Visibility has greatly improved in Missoula and Helena as the air is now GOOD there. However, the Bitterroot Valley, Beaverhead County, and Madison County are all still taking the brunt of the smoke, and this will continue into the evening. Cumulative smoke exposures in Hamilton are still UNHEALTHY, although hourly concentrations have just been MODERATE for the past few hours. This will likely go up as the evening continues on and more smoke is produced. Butte and Bozeman are also being affected by these fires, as well as fires nearby in Montana. Cumulative air quality in Butte is UNHEALTHY, but hourly concentrations have dropped to GOOD for the past three hours, and visibility has also improved there. Cumulative air quality in Bozeman is also UNHEALTHY, but like Butte, hourly concentrations have just fallen to GOOD in the past hour. Smoke is still visible in the air but visibility has improved since this morning. The newest location with smoke impacts has been West Yellowstone, where hourly particulate concentrations have become MODERATE for the past few hours. Finally, the Livingston area is still very smoky and is at least UNHEALTHY FOR SENSITIVE GROUPS. Everywhere else in Montana—northwest, central, the hi-line, and southeast—are all 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 2:45 this afternoon. Clouds are across eastern Montana in association with a cold front. Smoke plumes are visible again from Idaho and are blowing over into southwestern Montana. 

This is the visible satellite image from 2:45 this afternoon. Clouds are across eastern Montana in association with a cold front. Smoke plumes are visible again from Idaho and are blowing over into southwestern Montana.


 
This is some of the clearest air that Missoula has seen in a while, thanks to a slight change in wind direction!

This is some of the clearest air that Missoula has seen in a while, thanks to a slight change in wind direction!


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).

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 pink 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 

Unlike Missoula, Hamilton still has not seen a clearing from the smoke. This webcam image in the middle of the afternoon looks pretty dark because of all the smoke.

Unlike Missoula, Hamilton still has not seen a clearing from the smoke. This webcam image in the middle of the afternoon looks pretty dark because of all the smoke.

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  
  Very Unhealthy  
  Unhealthy  Bozeman B24
Butte B24, B8
-Both hourly concentrations are GOOD-

Hamilton B24, B8
  Unhealthy for Sensitive Groups  Helena B24
Billings B24
-Both hourly concentrations are GOOD-
  Moderate

 West Yellowstone B8, B1
 

  Good

 Libby
Flathead Valley
Frenchtown
Missoula
Seeley Lake
Great Falls
Sidney
 

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.