Statewide smoke update: heat and lingering impacts

Over the weekend, smoke drifting in from fires in Central Idaho led to significant smoke impacts in Southeast Washington. 

Yesterday's satellite imagery showcased the smoke from Idaho impacting Southeast Washington. Smoke from the Bear Gulch Fire is also visible, as well as a new fire in British Columbia.

Satellite image from 2pm Sunday, August 24 showing smoke from fires in Idaho impacting Southeast Washington. A localized plume of smoke from the Bear Gulch Fire near Lake Cushman is also visible, as well as a narrow plume in British Columbia. Source: NASA Worldview. 

Monitoring sites in Clarkston and Pullman observed some of the highest PM2.5 concentrations of the season:

Hourly PM2.5 concentrations from monitoring sites in Clarkston and Pullman. Data accessed 11am 8/25/2025.

Hot weather combined with increased regional fire activity continues to produce widespread haze and moderate air quality across much of the state. The heat will continue into Wednesday morning. Smoke impacts in Southeast WA will continue through at least mid-week, although likely less impactful than the weekend's smoke due to shifting winds. Air quality will likely remain moderate with periods of USG. There may be occasional Unhealthy air quality in the Clarkston area. Lingering haze could extend as far north as Spokane. 

The Bear Gulch Fire remains active. The greatest smoke impacts will continue to be closest to the fire near Lake Cushman. Haze will be visible throughout the region.

Moderate air quality was observed yesterday in western WA and continues into today. While smoke from the Bear Gulch Fire is contributing to slightly degraded air quality, heat and stagnant meteorological conditions are also trapping pollutants at the surface. Light winds are limiting dispersion, allowing pollution to accumulate. It's likely that the PM2.5 currently measured at monitoring sites reflects both wildfire smoke and Secondary Organic Aerosol (SOA). SOA forms in the atmosphere when volatile organic compounds (VOC) emitted from vehicles, industrial processes, and trees and plants react with oxidants in the atmosphere, including ozone. Hot weather enhances ozone formation and increases the biogenic (trees and plants) fraction of VOC emissions.  Over the weekend, elevated ozone concentrations were observed along the Cascade Foothills of King and Pierce counties; similar conditions are expected today and tomorrow.

Critical fire conditions are expected today and tomorrow in the Cascades and Methow Valley. The heat will begin to ease on Wednesday; cooler temperatures may reduce fire behavior and lessen smoke impacts. However, smoke and haze may linger through the week. If new fires start, smoke impacts could increase. Keep an eye on current and forecasted conditions on the map at the top of this page, and we'll provide updates as needed.