Today's air quality update from Missoula City/County Air Quality Specialist, Sarah Coefield:
"I hope you're all ready for Pacific Northwest Smoke: The Return.
We had a nice couple days of clearer skies over the weekend as smoke from Oregon, California and Washington swept south of Missoula County. Unfortunately, the smoke from those fires is now under the influence of flow aloft that is pulling smoke from Oregon and California up to Washington and then swinging it to the east. There's already a fair bit of that smoke overhead, and it will be coming down later today to say hi and make friends with the local smoke.
The Pacific Northwest (PNW) smoke will cause widespread haze and will undermine the benefits of afternoon convection. Our smoke may lift up late this afternoon, but the PNW smoke will come down to take its place.
This morning, our most pressing concern is still the locally generated smoke. The fires have been extremely active for the past couple days, and several of them continued to produce a lot of heat and smoke overnight. The smoke from these fires funneled down into valleys where it became trapped under strong inversions. The pooled smoke will continue to linger in the valleys for several hours this morning. We are under a high pressure ridge that will delay inversion break, and some areas may not start to see smoke lift off the valley floor until noon. Once those strong inversions break, there should be some improvement for communities dealing with the thickest smoke (Seeley Lake and Florence).
For the rest of us, inversion break will mean worsening air quality. There is a lot of smoke overhead, and as inversions start to break, those of us in the larger valleys will see the local smoke mix down into our breathing space. The air quality was already pretty crummy in Missoula this morning, and it's about to get worse.
As the day wears on, we are going to see a lot of competing factors that will complicate our chances for air quality improvement. To begin, we are under a strong high pressure ridge. High pressure limits smoke's ability to go anywhere. It acts like a lid over the region and can result in significant smoke build up. To counteract this, we are also looking at very warm temperatures today, which, if they start to rise soon enough in the day, could result in convective lift to at least move the smoke off the valley floor. Unfortunately, convection will be delayed by strong inversions, and those inversions are further strengthened by the thick overhead smoke that may prevent us from even reaching the projected high afternoon temperatures. And of course, if we do start to see some atmospheric mixing and nice convection in the afternoon, the overhead PNW smoke will mix down and cause continued smoke impacts.
What I'm saying is, our opportunities for decent air may be pretty limited today. Currently, the best air quality is in Frenchtown and Alberton, where they are enjoying pleasantly Moderate air. These areas aren't dealing any pooled smoke, but there is a lot of overhead smoke from the PNW as well as some overhead smoke from the local fires. Conditions in Frenchtown and Alberton are likely to start deteriorating later this morning as local smoke mixes down, and then later this afternoon there may be additional deterioration from PNW smoke.
(If that sounds odd, know that the PNW smoke is at a much higher elevation than the local smoke. Our mixing height is likely to increase enough to reach the PNW smoke by late afternoon.)
Conditions are Unhealthy for Sensitive Groups in Rock Creek and are likely to become Unhealthy in the next hour or so. Missoula and Lolo are seeing smoke from the Lolo Peak Fire, Arlee and the Potomac Valley are being hit by Liberty Fire smoke, and there's a ton of smoke from the Rice Ridge Fire stretching over the Swan Valley. As a result, air quality is already Unhealthy in Missoula, Lolo, Arlee, the Potomac Valley, the Holland Lake area and Condon. We can expect further deteriorating air quality through the morning hours at these locations.
When air quality is Unhealthy for Sensitive Groups, people with heart or lung disease, children and the elderly should limit prolonged outdoor exertion. 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.
Air quality is Very Unhealthy in Florence. Florence continues to bear the brunt of pooled Lolo Peak smoke. (Lolo had a rough night as well, but conditions had improved to Unhealthy by 3 a.m.) Air quality in Florence is currently Very Unhealthy and may hit Hazardous before inversions break. When the inversions to break, Florence should see improvement as the pooled smoke is finally able to move out of the area.
The smoke is really bad in Seeley Lake. Air quality is Hazardous, and it's been getting worse as the morning wears on. The 9 a.m. PM2.5 measurement was 961.7 ug/m3. Conditions in Seeley Lake should start to improve by noon, but Seeley Lake may not see complete clearing today. The high pressure will limit smoke movement and overhead smoke will mix down in the afternoon.
When air quality is Hazardous, all people should limit or avoid outdoor exertion and leave the area or stay indoors with filtered air when possible. Anyone experiencing symptoms of heart or lung disease associated with smoke exposure should contact their health care provider. The Health Department has recommended Seeley Lake residents get out of the smoke if they are able to. You can find the official recommendation and some helpful resources online.
Our best bet for improvement will be around 4:00 p.m. today - temperatures and mixing heights will increase at that time, as will ground and transport wind speeds. However, there is a good chance that while we may see some improvement, there will still be localized smoke impacts and there will be widespread haze from PNW smoke. Keep in mind that we are likely to see another day of extremely active fire behavior. This means more smoke pooling over night and more smoke impacts tomorrow.
The Bitterroot Valley will be hit by Idaho smoke this afternoon, which will complicate Florence's ability to see any prolonged air quality improvements."
