Fire Season 2018 Winds Down…A Lucky Year in NW Oregon & SW Washington

September 13, 2018

5pm Thursday…

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This has been a tough fire season again across the West.  Although some spots have been spared in our region.

In Oregon there have been two “hot spots”through the fire season.  That’s the numerous lightning-caused fires across SW Oregon that have burned for two months.  And then several very large fires (some from lightning, some human-caused) across north-central Oregon.

Assuming some huge new fire doesn’t break out in the next few weeks, (unlikely looking ahead weatherwise) I think we are well past the big danger period for this season.

Who got lucky in our area?

There were no major fires across most of NE Oregon, the northern Oregon Cascades, all of NW Oregon, and all of SW Washington.  As of this moment total acreage burned across the Pacific Northwest is significantly DOWN from last year as well…around 700,000 acres vs 1,100,000 or so last year.

Considering late spring and early summer was the driest or 2nd driest on record in our area I think we were very lucky.  It’s most likely due to lack of lightning.  For a second season it seems we had very little thunderstorm action both in the mountains and down here in the lowlands.  I don’t have the stats to back that up (yet), but I’ll find them eventually.

Fire Fuel Moisture Oregon2

The showers and cooler weather most of the time since late August has helped tremendously in the Cascades.  Check out the Log Creek “1000 hr fuel” moisture level this summer:  the black line is this year, yellow is last summer.   Blue is the average…you notice the woods in that area are typically driest in late August and then moisture increases in September.

Fire Fuel Moisture Oregon

This year we were running exceptionally dry through the third week of August, but then some showers brought us back up to average for that time of year.  Then you see showers the past few days have brought fuel moisture back ABOVE average for early September.  With more showers through the weekend and again later next week I have no reason to believe those fuels will dry out again.  Notice that huge dump of rain last September that put an end to the fire season.

To summarize:

  1. Much of Oregon remains dry, but cooler temperatures have lowered fire danger even in those spots
  2. Fire Season 2018 is winding down quickly west of and on the west slopes of the Cascades.  It’s not over yet, but the chance of large fires developing is going downhill.
  3. For the 2nd consecutive year fire season is ending a bit early; I doubt anyone is complaining!

As for weather…looking ahead I see a continuation of below-average temperatures through next week but Monday through Thursday should be dry.  Note the ECMWF ensemble high temperature forecast looks like early October

KPDX_2018091312_eps_min_max_15

I love this graphic…the 24 hr accumulated precipitation product from the ECMWF ensembles.   You can glean lots of information quickly.  First the bottom section.  That’s the ensemble “average”.  You clearly see the best chance for significant rain is centered right on Sunday.  Looks like every single ensemble member (each is a horizontal line above) shows a tenth of an inch or more.  Maybe 20% give PDX more than 0.50″.  Then there is good agreement on a dry spell Monday through at least Wednesday and likely into Thursday as well.  We’ll dry out a bit.  But some decent hints also that late next week and the following weekend could be showery.  Good meteorological stuff!

KPDX_2018091312_eps24_precip_360

Enjoy the mainly dry weather Friday, I think there will just be a few light showers popping up late in the day…many of us stay dry.

Chief Meteorologist Mark Nelsen