Wildfire

Major Fire Breaks Out Near Skykomish, WA

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5:30 pm

This weather event has played out as expected so far, with gusty, very dry easterly winds over parts of Western Washington and Western Oregon and rapid growth on existing fires. Smoke has also spread north over the Willamette Valley and Puget Sound as easterly flow weakens and veers to the north. Fire danger has already decreased substantially for SW Washington and Western Oregon, and the Red Flag Warnings over those areas will expire tonight. Fire danger is now higher over Western Washington due to stronger offshore gradients there, and Red Flag Warnings remain in effect until tomorrow evening.

However, we now have a new, destructive wildfire in the North-Central Washington Cascades. This fire, named the Bolt Creek Fire, began early this morning and has already grown to over 2,000 acres by noon under the influence of these strong, dry offshore winds. The exact cause of the fire has yet to be determined, but it was a human-caused fire.

As always, Twitter has been a fantastic resource for real-time observations and updates on this fire. Here are some photos/videos of the flames.

Fire behavior is currently extremely active, with wind-driven runs and “long-range spotting,” which is where burning embers blow downwind and create new fire starts. Because the fire is occurring in terrain, these embers can travel very long distances before finally settling down and beginning new blazes. The photos from the DNR show how rough and remote the burning region is, and long-range spotting will play a significant role in allowing the fire to grow westward.

Around noon today, the Washington DNR issued a Level-III (“Go Now!”) mandatory evacuation order for all citizens north of Highway 2 from Skykomish to Index, and Highway 2 is closed along a 17-mile stretch from Gold Bar to Skykomish (Index is about halfway between these locations). Other citizens in nearby areas are under Level-II evacuation orders, meaning they must be ready to leave at a moment’s notice if fire behavior worsens and they are upgraded to a Level-III.

The fire has even seen some light pyrocumulus development, which are convective clouds spawned from the intense heat of the fire. Clouds reached up to 20,000 feet – not exceptional – but nothing to shake a stick at, especially for a fire less than 12 hours in the making. Husky fans at today’s football game have been able to spot the pyrocumulus through the haze all the way from Husky Stadium

The fire is also visible on radar due to ash blowing downwind. You can also see plumes from the Cedar Creek Fire in Oregon, as well as more diffuse echoes over Western WA/OR where light ash is suspended.

Smoke Update:

Smoke has been increasing in Seattle and Portland throughout the day as southerly winds aloft push the Cedar Creek Plume through the I-5 corridor. I’ve been blogging and tweeting near Pike Place Market with a view of Puget Sound, and West Seattle across Elliot Bay has become more and more difficult to see as the afternoon has progressed. The satellite animation below shows how the smoke has moved north throughout the event.

Air quality has decreased throughout the day across the Pacific Northwest as smoke has moved northward, and is now in the “unhealthy” level for most regions, with areas immediately downwind of major fires experiencing falling ash and “hazardous” conditions. As bad as the air quality is here, it is still much, much better than it was during the September 2020 fires, where the entire Willamette Valley was well into the “hazardous” category for the better part of a week.

Air quality indices around 5pm 9/10/2022. 151-200 is “unhealthy,” 201-300 is “very unhealthy,” and anything above 300 is “hazardous”
Credit: purpleair.com

Smoke will persist through tomorrow, with perhaps a *slight* clearing trend tomorrow afternoon/evening as flow becomes onshore. However, conditions will be much better by Monday afternoon, when stronger onshore flow finally returns and the smoke gets pushed out of the area for good.

Smoke forecast at 11am Monday 9/12/2022. Onshore flow on Monday will help push smoke east of the Cascades, and by Monday afternoon/evening, air quality should be at healthy or moderate levels for most of Western Washington and Oregon.
Credit: NWS HRRR-Smoke Model

Next week looks seasonable, with highs reaching the upper 60s/low 70s for Seattle, the upper 70s for Portland, and no westside fire threats whatsoever. Until then, exercise extreme caution until the Red Flag Warnings over Western Oregon and Western Washington expire, and heed evacuation orders if requested.

Charlie

Featured image credit: Washington State Department of Natural Resources

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