Air Quality Update for Western Montana, August 9, 2017

Aug 9, 2017
Originally published on August 9, 2017 8:36 am

Today's update and forecast, once again, courtesy of Missoula City-County Air Quality Specialist Sarah Coefield:

"I'm pleased to report that the air at ground level in Missoula is a relatively decent Moderate. The air far above us, on the other hand, is filthy. The Canadian smoke that was starting to cover the skies last night is here in full force this morning. There are happy fluffy white clouds visible in the satellite photo this morning, but they aren't anywhere near Missoula. That overcast, gray sky color you woke up to is entirely due to smoke. Fortunately, we won't see much atmospheric mixing until noon or a little bit later, so whatever impact the Canadian smoke may have is likely to be held off until at least this afternoon. When the smoke mixes down, conditions may deteriorate to Unhealthy for Sensitive Groups.

The atmosphere stayed fairly mixed overnight due to a weak cold frontal boundary across southwestern and west central Montana. This led to slightly warmer early morning temperatures than what we saw yesterday as well as a delayed onset of smoke settling into valleys. The Rice Ridge, Sunrise, Lolo Peak, Hidden, and Little Hogback Fires were all actively burning overnight, and we're starting to see some impacts from that activity this morning. As the morning progresses we've started to see conditions deteriorate in communities near active fires.

Air quality in Seeley Lake is currently Hazardous. It took several hours, but smoke did start settling into Seeley Lake at about 6 a.m. and conditions have rapidly nose-dived. The air quality is likely to get worse before it gets better for the next couple hours. The inversion will start to break as the sun angle increases and temperatures rise. Later this morning we should, once again, see rapid improvement and decent clearing of the smoke after 1 p.m.

When air quality is Hazardous, all people should limit or avoid outdoor exertion and stay indoors when possible. Anyone experiencing symptoms of heart of lung disease associated with smoke exposure should contact their health care provider.

Conditions in Lolo are currently Unhealthy. As with Seeley Lake, we didn't really start to see impacts until about 6 a.m., and the smoke in Lolo has been making up for lost time. The Canadian smoke shroud is making it difficult to pick out our local fires, but we can pretty safely assume Lolo is being hit by smoke from the Lolo Peak Fire, and possibly also the Little Hogback Fire. Conditions in Lolo should start to improve by this afternoon. The southern part of the Missoula Valley may also see some of the smoke that is hitting the Lolo area.

When air quality is Unhealthy, people with heart or lung disease, smokers, children and the elderly should limit heavy or prolonged exertion and limit time spent outdoors. People with asthma should follow their asthma management plan. People experiencing symptoms of heart or lung disease associated with smoke exposure should contact their health care provider.

Conditions in Arlee are Unhealthy for Sensitive Groups, and may reach Unhealthy before they start to improve later this morning and afternoon. As with Lolo, I can't pinpoint the plumes hitting Arlee, but based on past experience, it's likely smoke from the Liberty Fire draining into the Arlee area.

When air quality is Unhealthy for Sensitive Groups, people with heart or lung disease, children and the elderly should limit prolonged outdoor exertion.

We are seeing Hazardous conditions along the I-90 corridor near the Sunrise Fire. It looks like the worst of it is still west of Alberton, and the east/northeast breezes in the forecast should continue to keep Sunrise Fire smoke out of Missoula County.

Aside from the confounding factor of Canadian smoke that may mix down later this afternoon, I expect conditions to generally improve across Missoula County by late morning and early afternoon. We are still seeing easterly and northeasterly surface and transport breezes, which should keep the Lolo Peak and Sunrise smoke headed toward Idaho. The Little Hogback and Hidden fires will likely take turns pouring smoke into the Bitterroot Valley today, which may lead to fluctuating air quality from Stevensville to Lolo.

There is an increased chance of thunderstorms this afternoon, which will potentially lead to some active fire behavior due to increased winds and outflow from passing storms."

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