Lingering smoke in the Cascades

Lingering smoke continues near active smoldering fires. Today's satellite imagery shows visible smoke pooled in valleys near the Sisi and Little Giant Fires, as well as the Luna and Border 2 Fires in the North Cascades. The Three Queens and King Fires also continue to produce moderate smoke.

Satellite imagery from Sept. 18 (Terra/MODIS). This morning's (9am) hourly PM2.5 concentrations shown in the circles.

As long as these fires smolder, nearby and downwind communities will continue to experience smoke impacts. Areas including Cle Elum Lake, Lake Wenatchee, Lake Chelan, and Ross Lake will observe intermittent smoke, with Stehekin experiencing the most persistent smoke due to its proximity to the Sisi Fire. Warm and dry weather will continue for at least the next week, with only a chance of minimal rain next Friday. Until widespread rain arrives, expect the familiar pattern of overnight and early-morning smoke pooling in valleys and downslope areas, followed by gradual improvement throughout the day.

Low hanging smoke over Cle Elum this morning due to smoldering on the Three Queens Fire.

With the peak of wildfire season behind us, agricultural burning is now underway in the Columbia Basin and Idaho. Communities in southeast Washington may see occasional periods of moderate smoke from agricultural burning throughout the rest of the month. Prescribed burning will also start to increase as we transition into fall.

This Year's Wildfire Season - Compared to Prior Years

This year's wildfire season began quickly with numerous lightning ignitions in mid-July and continued steadily through August. The plot below highlights daily average PM2.5 concentrations that were USG or worse over the last 15 years, as observed by the statewide monitoring network (no purple air sensors). This year was characterized by a fast start, minimal relief, and now a slow finish as smoke from lingering fires continues to impact nearby communities. This is in contrast to other years which sustained more smoke impacts through September or experienced more intermittent smoke impacts spread across the season. 

Smoke in the Cascades - But More Rain this Weekend

It's that time of year when we all start to wonder if wildfire season will end soon.  Fire growth has mostly been light this week, but there are still active incidents and smoke affecting nearby communities in the Cascades.  Hot-spots are still being detected by satellite at the Border 2, Luna, Sisi, Little Giant, Three Queens, and King fires. There was also a new vegetation fire in Walla Walla county yesterday that grew quickly, but the Skyrocket Fire progress has been stopped by fire crews and there were only minimal smoke impacts.

Winds today are light, keeping smoke near active fires.  Cle Elum, Chelan, Leavenworth, and other nearby communities are experiencing moderate to unhealthy smoke impacts.  Stehekin has been experiencing more concerning smoke impacts, due its proximity to the Sisi fire, but fire crews are working hard to increase containment with water drops and fire lines. 

Smoke impacts this week in Chelan, Cle Elum, Entiat, Leavenworth, and Stehekin

Easterly winds are expected to increase tonight and into tomorrow, which will bring moderate smoke into the mountain valley towns of Whatcom, King, and Snohomish counties tomorrow morning.  The good news is that more rain and cooler weather is on the way Saturday night and into Sunday, which will clear out smoke and reduce fire activity.  Over an inch of rain is expected near the Three Queens and King fires.  However, less rain is expected further north.  The Border 2 and Luna fire in Whatcom county aren't expected to benefit, while the Sisi and Little Giant fires in Chelan county will likely see minimal rain.

Total rain expected this weekend - courtesy of Windy.com (NAM model)

Overall, moisture this weekend will help decrease fire activity significantly.  However, cooler temperatures will cause lower mixing heights which keeps smoke near the surface. We don’t expect any new large scale incidents, but current fires still represent a substantial source of smoke for the nearby communities in the Cascades.  Warmer and drier conditions are also expected next week, which will allow those pesky fires to stick around a bit longer. 

The 2026 Wildfire Season Finally Slows Down

Rain and Cooler Temperatures - What Comes Next for Fire Season? 

Precipitation totals over the past 72 hours have favored southwest Washington, the Olympics, and the Blue Mountains. In fact, windward portions of the Olympic Mountains recorded 2-4 inches of rain from this system so far. Rain amounts of 1-2 inches were also observed in portions of the south Cascades. 

Click to enlarge. Precipitation totals from 1200 Tuesday to 1200 Friday. Data via NOAA. 

Even with the pattern change to cooler and damp, the map below highlights portions of state that received less than 0.25" of rain this week. Dry spots focused in the lowlands of northwest Washington and lower elevations east of the Cascade crest. The Little Giant Fire notably received minimal precipitation. 

Areas with less substantial precipitation (0.25" or less) from 1200 Tuesday to 1200 Friday. Data via NOAA. Contours drawn by DNR meteorology staff.

In the near-term, the fire environment is slowing quite a bit even for areas that haven't received a lot of rain. That is because cooler temperatures and higher relative humidity allows fuels to absorb moisture from the air and become less flammable. Looking ahead, additional light precipitation is expected this weekend but primarily in areas that have already received it. For example, the Little Giant Fire has not received a quarter inch of rain yet and only has around a 20% chance to receive a quarter inch of additional rain. Regardless, near to below normal temperatures and minimal wind will keep the fire environment relaxed this weekend. 

Probability of additional precipitation > 0.25" through Saturday night. Data via Global Systems Laboratory (GSL)/NOAA.

Then, a gradual warming and drying trend is on the horizon for the middle of next week, followed by a lot of uncertainty in the weather pattern mid-month. With the warming temperatures next week, areas that missed out on significant rain should quickly return to a state that would support fire spread. This is especially true in lighter, flashy fuels such as the grass and sagebrush of the Columbia Basin. In contrast, heavily forested areas that received a lot of rain will struggle to return to conditions that prompt any concern for significant wildfire spread (e.g. Olympic mountains). 

Probability of temperatures exceeding 80 degrees Fahrenheit next Wednesday, September 9. Data via Global Systems Laboratory (GSL)/NOAA.

In general, we are entering the time of year where emerging large wildfires just aren't very common across the state. In fact, for the past 25 years (2001-2025) Washington only averages about one 1000+ acre fire annually beginning on or after September 10. 

That said, existing forest fires like Little Giant could still grow and produce increased smoke if favorable fire weather conditions return over the next few weeks. Given the uncertainty in the forecast, it is certainly possible that fire activity could increase again -- just probably not to August levels.

Air Quality Improvement

Air quality has improved in recent days, even for areas closer to the large fires in the Cascades. Between August 22 and September 1, monitors in Cle Elum, Leavenworth, Peshastin, Entiat, and Chelan were experiencing almost daily periods of air quality reaching UNHEALTHY FOR SENSITIVE GROUPS to UNHEALTHY, with a few spikes into VERY UNHEALTHY or HAZARDOUS observed. 

Since Wednesday, however, hourly readings have primarily been GOOD to MODERATE. 

Department of Ecology air quality data for Cle Elum, Leavenworth, Peshastin, Entiat, and Chelan from August 22 to September 4.

In general, minimal changes are expected in the near-term and most communities across the state will experience GOOD air quality for the holiday weekend. If you've been dealing with smoke and finally have better air quality, it's a great time to open those windows! Areas very close to large fires in the Cascades, however, will still experience periodic smoke impacts -- particularly in the morning hours. 

Mop-up work on the Little Giant Fire, September 1, 2026. Photo via Donovan Smith, accessed via InciWeb.