Sunday, August 4, 2019

Wildfire Smoke Returns to Western (and Eastern) Washington

Well, you knew it couldn't last. 

Wildfire smoke is back, but fortunately it should be relatively sparse and short-lived here in western Washington and Oregon.  Many of you noticed the arrival of a thin haze the last few days, a combination of smoke from Asia, Alaska and southern Canada. 

Here are two pictures from the SpaceNeedle cam at noon on August 1st and this morning (August 4th).   Can you see the difference?  Mt. Rainier is visible in one and not the other and the mountains are less distinct today.



Why worst today?  Because the upper trough over us moved out and a ridge of high pressure developed over the northeast Pacific, which resulted in northerly flow pushing south our of  Alaska (see upper level map at 2 PM on Saturday).


And now we have a new player...a major grass fire in eastern Washington west of Spokane on the Colville Reservation:  the Williams Flat fire.   Initiated by lightning on August 2nd, the fire is now over 10,000 acres and is filling eastern Washington with smoke...and a bit of it is heading towards Puget Sound! 

The GOES-17 visible satellite image around 7 AM  today really shows the smoke (see below), but keep in mind that the low sun angle at that hour really highlights the smoke.


The same satellite image around 1:30 PM is not as scary...you can see where the fire is and if you look closely you can see some thin smoke heading up Snoqualmie pass.


With this smoke blowing in from the north and east, air quality has started to deteriorate in the West. 

Below is the concentration of small particles (PM2.5), the kind that moves deep into your lungs, at Seattle from July 1 to today.  You will note the high values on July 4th and subsequent nights from formal and informal fireworks.  Subsequently, the values stay low, roughly around 6 (micrograms per cubic meter if you are interested).  Then yesterday it jumped to around 15 and stayed up...that is the smoke.    Nothing like the crazy values of last summer (which got over 100 for a few days), but noticeable in visibility.


The situation was much worse in Spokane, a short distance from the fire, where the small particles jumped to around 100 before the wind shifted and blew the smoke to the south.


What will happen next?  Most grass fires surge and die rapidly.  The latest NOAA/NWS HRRR smoke model forecast for 11 PM tonight, 11 AM Monday, and 11 PM Monday night suggests that most of the smoke will stay east of the Cascade crest and spread southward into Oregon and west into Idaho.




At this point, there is no reason to expect unhealthful air quality in western Washington or Oregon...but stayed tuned.

9 comments:

  1. Every year, beginning of August. Right on schedule.

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  2. Cyanobacteria in my lake, Smoke in my air, and Hey, it's going to be 100 all week.

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  3. Meh, it looks like this will pass. Last year it started by July 30, year before was August 1 I recall. It's August 5th and sky is still blue. Again, recall past two years 25+ days out of the month the sky was fully grey. This is not at all the same.

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  4. I saw the haze yesterday and scrapped my plans for stargazing last night. And then awoke to learn that I missed the aurora!!!

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  5. Can we expect any fall-out (meant literally or not) from the Russia explosions?

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  6. Aurora? I should have looked for it: I was camp deep in the North Cascades, very dark sky.

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  7. Following June 2019 as the warmest June on record for the planet, preliminary data suggest that July 2019 was the warmest or second warmest month on record. All of this despite being in only a very weak El Nino condition.

    So much for the solar minima advocates.

    https://www.ncdc.noaa.gov/sotc/global/201906

    https://public.wmo.int/en/media/news/july-matched-and-maybe-broke-record-hottest-month-analysis-began

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  8. It looked less smoky over Western Whatcom County today.

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  9. A very interesting piece on forest fires can be found by searching for "old flames the tangled history of forest fires" which should bring up a story by Hugh Powell from the allaboutbirds website. As a forest owner I still would be upset if my acreage burned, but in the big picture it's totally natural, even the 100-year huge fires that apparently destroy the forest.

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