Over the weekend, nearly every part of the state experienced smoke impacts, with many air quality monitors observing unhealthy or worse conditions. Sunday's satellite image shows the swath of smoke across the state:
|20 Aug 2023 19:01Z - NOAA/NESDIS/STAR GOES-West|
Easterly winds plus smoke from both local and Canadian fires led to the poor air quality we observed over the weekend. Two fires in the Spokane area (Gray Fire and Oregon Road Fire) led to hazardous air quality in Spokane.
We're already seeing improvements in western Washington with the arrival of westerly onshore winds. The smoke will likely linger through today but skies should be clear by tomorrow morning. Air Quality Alerts are in place through midnight tonight for the following counties: Island, King, Pierce, San Juan, Skagit, Snohomish, Whatcom. An Air Quality Alert is in effect until 5pm today for Clallam County.
Central and Eastern WA
Air quality will also slightly improve today in Central and Eastern Washington with southeast winds, although there is uncertainty in how much relief Central Washington will experience. Forecasted southwesterly winds tonight and tomorrow will increase smoke in the region. Air Quality Alerts comprise all Central and Eastern WA counties, and are extended through noon on Wednesday.
Expect significant clearing on Wednesday. Unfortunately, forecasted northerly winds could bring Canadian smoke to Northern Washington on Thursday and Friday. We'll update the blog as necessary.
We observed interesting smoke dynamics in the atmosphere on Saturday as the smoke was transported higher up in the atmosphere but then mixed down to the surface. Ecology's air quality sensor at the Mt. Rainier visitor center (elevation 5400') observed elevated PM2.5 concentrations 3 hours before the closest purple air sensor at Longmire (elevation 2700') and 8 hours before the purple air sensor in Ashford (elevation 1700').