Air quality across the Pacific Northwest has improved substantially compared to the smoke-choked weeks of August and early September, as cooler temperatures and a series of frontal systems push residual smoke out of populated areas. However, residents living near active fire perimeters in Kittitas, Chelan, Okanogan, and Walla Walla counties in Washington, and near the Umatilla National Forest in eastern Oregon, may still experience localized smoke and reduced visibility during morning and evening hours when smoke settles into drainages.

What Changed This Week

A notable shift in the region's fire weather pattern occurred in late September, with temperatures dropping below seasonal normals across Oregon and Washington. September precipitation was above normal for northern California and much of the Northwest, according to NIFC Predictive Services, helping to tamp down fire behavior and reduce the smoke load entering the atmosphere from active incidents.

With wildfire smoke now largely localized to areas near active perimeters — rather than transported regionally by high pressure — the air quality index (AQI) across most major population centers including Portland, Seattle, Spokane, and Boise has returned to Good or Moderate levels.

Where Smoke May Still Be a Factor

  • Kittitas County, WA — Smoke from the Three Queens and King fires may pool in valleys east of Snoqualmie Pass during overnight and early morning hours, particularly in the Cle Elum and Roslyn areas.
  • Chelan and Okanogan counties, WA — Residual smoldering from the Sisi, Little Giant, and Ptarmigan fires can produce localized smoke, especially in narrow mountain drainages.
  • Walla Walla County, WA / Umatilla County, OR — Active mop-up on the Hatch Grade Fire may continue to produce smoke visible from Highway 12 and surrounding communities.
  • Eastern Oregon — Umatilla NF — Smoke from Hagen Fire mop-up operations may drift toward Pendleton and the Columbia River Plateau under certain wind conditions.

Protecting Yourself During Smoke Events

Health officials recommend that sensitive groups — including children, the elderly, and those with respiratory or cardiovascular conditions — take extra precautions even during moderate AQI readings:

  • Monitor AirNow.gov for real-time AQI data by ZIP code
  • Keep windows and doors closed during periods of elevated smoke
  • Run HVAC systems on recirculate mode rather than fresh air intake
  • Use N95 or KN95 respirators if outdoor activity is necessary during smoky conditions
  • Postpone strenuous outdoor exercise on days with elevated AQI

Looking Ahead

The October outlook from NIFC Predictive Services indicates that while a warm and dry pattern is expected to reassert itself during the first half of October — with temperatures running 5-15 degrees Fahrenheit above normal across most of the West — the seasonal transition should limit the duration of any significant fire weather windows. The Pacific Northwest is expected to see more frequent frontal passages through November, further improving air quality and suppressing fire activity across the region.