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Wildfire Smoke Update
for
Tuesday, September 11, 2012 3:21 PM

Satellite Photos | Locations and Smoke Conditions


Today's Report and Forecast Today's Summary
Although there are some locations in southwest Montana where particulate concentrations are still a bit high, air quality state-wide is much better so far this afternoon than it has been in recent days. By this time Sunday and Monday, smoke plumes from Idaho and western Montana were very visible on satellite images, and smoke was increasing rapidly. Today, under less-extreme fire weather conditions, smoke plumes are not nearly as ominous. Hourly particulate concentrations in the Bitterroot Valley have fluctuated between MODERATE and UNHEALTHY FOR SENSITIVE GROUPS today, though cumulative smoke averages is still VERY UNHEALTHY. Particulate concentrations in Butte and Bozeman have also trended down throughout the day today, and both are GOOD for the latest hourly observation, though both still run UNHEALTHY for long-term averages. The story is similar in Helena, Great Falls, and Sidney, where long-term particulate averages are still UNHEALTHY FOR SENSITIVE GROUPS, even though hourly concentrations today have been GOOD. On a day like today, it is important to know the difference between the hourly and cumulative or long-term concentrations. Because the cumulative concentrations are averaged over a full 24-hour period, this information particularly pertains to those who are outside for most hours of the day. For example, campers or backpackers would want to know these numbers to take the appropriate precautions. However, people who are only outside for very brief periods during the day would want to focus on the hourly concentrations. These near real-time numbers will be most beneficial to someone who may only spend a short while outside perhaps after work. Of course, for those who are outside of the monitoring locations or when smoke conditions change very rapidly, the visibility guidelines would be the best bet for an instantaneous assessment of the air quality.

For the rest of the evening, those smoke plumes across Idaho and western Montana may grow and spread, but it should not be like what we have seen recently. So, even though smoke is being produced, it will not be as heavy and will not have such a detrimental effect on the air quality downwind. The direction of high atmospheric winds would blow any smoke plume generally to the east for the rest of the night. Temperatures will be very cold tonight, with some of the coldest temperatures we have seen since spring. Don’t forget to cover sensitive plants! Tomorrow, winds will continue to lessen in intensity, though the afternoon will still be breezy. The air will remain dry, but the winds are not strong enough and humidities will not be low enough to warrant any fire statements from the National Weather Service. Fire activity will not be very erratic tomorrow, though wildfires will continue to burn and produce smoke. The heaviest air quality impacts tomorrow will mostly stay confined to the Bitterroot Valley and south of I-90 through Livingston. Smoke will be visible north of I-90, near Helena, but air quality impacts should be minimal. By Thursday, a ridge of high pressure slowly starts to build back in and temperatures will start to warm back up. Atmospheric winds will change direction through Friday, when winds will again prevail from the west and southwest. This will put west-central Montana downwind of the wildfires again, so smoke may return, depending on fire activity. Saturday will be similar to Friday, with a west wind blowing potential smoke east across the state. By early Sunday, a cold front will start to drop from the northwest to help clear the smoke and potentially set up the Northern Rockies for a chilly week.
Hourly particulate concentrations in the Bitterroot Valley have fluctuated between MODERATE and UNHEALTHY FOR SENSITIVE GROUPS today, though cumulative smoke averages is still VERY UNHEALTHY. Particulate concentrations in Butte and Bozeman have also trended down throughout the day today, and both are GOOD for the latest hourly observation, though both still run UNHEALTHY for long-term averages. The story is similar in Helena, Great Falls, and Sidney, where long-term particulate averages are still UNHEALTHY FOR SENSITIVE GROUPS, even though hourly concentrations today have been 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 2:30 this afternoon. Smoke plumes are faintly visible across eastern Idaho. 

This is the visible satellite image from 2:30 this afternoon. Smoke plumes are faintly visible across eastern Idaho.


 





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 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.

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  Hamilton B24
  Unhealthy  Butte B24
Bozeman B24
-Both hourly concentrations are GOOD-
  Unhealthy for Sensitive Groups  Sidney B24
Helena B24
Great Falls B24
-All hourly concentrations are GOOD-
  Moderate

 West Yellowstone B24, B8 

  Good

 Libby
Flathead Valley
Frenchtown
Missoula
Seeley Lake
Billings
 

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.