Weekly Recap and Labor Day Weekend Weather and Smoke Outlook

Weekly Recap

Fire danger began its anticipated trend upward this week, highlighted by Tuesday afternoon which saw gusty winds and low relative humidity along the east slopes of the Cascades and across the Columbia Basin. This was highlighted by the Bauer Coulee Fire at exit 206 along I-90. 

The fire intermittently shut down eastbound I-90 and both directions of SR-21 Tuesday afternoon and evening. A large smoke plume was observed in Ritzville. 

Smoke from the Bauer Coulee Fire as seen from Ritzville around 1:30 p.m. Tuesday. (Courtesy: X/@ac_ws)

Air quality degradation caused by the fire was localized and mostly noticeable in rural areas along SR-21 and local roads just to the east of the fire. An air quality monitor in Ritzville did show an uptick in PM2.5, but the Air Quality Index did not reach Moderate levels.

Air Quality Index in Ritzville showing a brief uptick Tuesday afternoon.

As of Wednesday afternoon, the fire was 100% contained after burning 1,600 acres.

Labor Day Weekend Weather and Smoke Outlook

The primary smoke concern for this weekend will be from sources out of state. Friday morning air quality observations near Boise ranged from Unhealthy to Very Unhealthy. Some of this smoke will drift north and may impact Southeast Washington this weekend, including Colfax, Pullman, Pomeroy, and Clarkston. By the time it reaches Washington, the greatest smoke concentrations will be several thousand feet in the air, but some may settle at the surface overnight leading to pockets of Moderate air quality. The best chance for this to occur will be Sunday and near-surface smoke may linger into Monday.

A secondary concern will be for smoke output from the Williams Mine Fire burning just north of Trout Lake. Latest reports from the fire indicate increased smoke activity within the containment lines as fuels continue to dry out. With light easterly surface flow expected this weekend, down valley locations could see fluctuations between Good and Moderate air quality.

Elsewhere across the state, air quality is expected to be Good this weekend. Dry conditions are expected with temperatures trending well above normal on both sides of the state.

Fire danger increases Monday with all fire weather hazards coming into play. There will be a 30-50% chance of thunderstorms in the north Cascades. There will also be a 20-30% chance of thunderstorms for the central and southern Cascades as well as the Blue Mountains.

A push of westerly winds is expected by late Monday morning through the Cascade gaps. Peak gusts currently look to be in the 30-40mph range, focused on the Columbia Gorge and the usual windy spots on the east slopes of the Cascades.

A map depicting forecast 24-hour max wind gusts ending 11 p.m. on Monday, September 2.

Relative humidity is expected to gradually increase from west to east Monday afternoon, however, a few hours of elevated to near critical fire weather conditions may be observed as gusty winds overlap with relative humidity initially in the 15-20% range.

As we head into the holiday weekend, please remember that a burn ban remains in effect on all Department of Natural Resources lands, including campfires in fire pits and the use of charcoal briquettes. Additionally, fireworks are illegal on all DNR protected lands. Visit the DNR Burn Restrictions website for more information. Have a safe and happy Labor Day weekend!