Monday, October 5, 2009

Major Duststorm and Strong Winds Hit Eastern Washington. Damaging Winds Over NW Washington

Extraordinary winds struck eastern Washington on Sunday, with 30-40 mph winds being commonplace, with gusts reaching nearly 60 mph around Wenatchee and vicinity. The result a major duststorm that closed down I90 for a while and resulted in numerous multicar accidents, sending 11 people to the hospital. Visibilities had dropped to less than five feet at times and the powerful winds knocked down many of the apples still on the trees near Wenatchee. It was reported that the ground at some orchards had turned red with apples.

An amazing picture is shown above from one of the the NASA MODIS satellites, clearly showing the dust (the brown stuff oriented NW-SW). The strong winds came at a bad time.... farmers had plowed up their wheat fields in preparation for the next season and rainfall has been very low this year. Although this is one of the worst dust storms in a while, it happens relatively frequently--my book has a section on it.

So why the strong winds? We had a combination of cold high pressure in Alberta and southern BC and a strong low over eastern Oregon and vicinity. The result was the creation of very strong northeasterly winds aloft and an intense low-level pressure gradient (see graphic). You see how packed the lines (isobars) are...that is a HUGE pressure gradient.
The computer model forecasts were quite good with this event and the National Weather Service had timely forecasts out well before. Want to see a vivid video of how bad it was...check out http://www.youtube.com/watch?v=yr819WqZMak

But the fun doesn't stop there. Western Washington got part of the action too (but no dust storm alas). As the high pressure built into southern BC a large pressure difference was established down the Fraser River Gap, allowing air to accelerate to the SE in that near sea level gap. Bellingham got hit hard, with winds gusting over 40 mph--accompanied by downed trees and power outages. Again, the computer models had it...see the graphic of wind speed predicted for 8 am on Sunday. You can see the strong NE winds exiting the gap. One of the great things about this blog are the reports I get from many of you--and this event was no exception.

Abram R. ("Abe") Jacobson, Earth and Space Sciences/ University of Washington, was sailing east of Bellingham yesterday and reported seeing waterpouts to the lee (west) of Lummi Island produced by the intense shear produced by the interaction of the strong winds with the island. To quote a warning in his informative email:

"If there are waterspouts on the lee side of Lummi, be afraid. Be very afraid! Water spouts are severe weather."

12 comments:

andycottle said...

Thats quite incredible, yet intense dust storm. That dust storm even made news in the Seattletimes paper in the "B" section believe it was. I can imagine what it would be like at night to drive through all that dust. It would be scary!

Michael Dempster said...

Sailing east of Bellingham....must be one o' them land yachts. Wish I'd seen the waterspouts...any photos? Speaking of images, Cliff, is there any way to present your charts larger, so the legend are legible? Thanks. Love your blog!

Kevin Purcell said...

Try clicking on the images, Michael Dempster, the tumbnails are links to the full sized images.

mainstreeter said...

I was in Tri Cities/Yakima Saturday and thought about a second day over there, glad I came home early. Did see some good dust devils between Ritzville and Washtucna Fri afternoon.

Must read blogs said...

when we were living in pullman, in 1991, there were really high winds and thats when the 9 mile fire occurred. we had gusts around 40 and lots of dust.

MastaMailMasta said...

When I woke up Sunday morning and couldn't see across the river, I figured this was just fog. I was confused by the winds (only ~20 knots here) and the temp-dewpoint spread. None of the local airport METARs (I'm a pilot) were reporting either fog (FG) or blowing dust (BLDU) until later in the day. I didn't figure it out until I saw the MODIS images. Would have been interesting to talk to flight services Sunday to see if they were on top of it--the conditions from Richland (KRLD) to south of Moses Lake (KMWH) were instrument for sure.

Bham_Guy said...

Cliff, can you give us some more information on the waterspouts that were observed west of Lummi Island? Are these similar to dust devils over land?

Fleetwood said...

Yeah, it was not a good day for a bike ride! Going across I-90 on my usual ride was a bit of an adventure.

MaryAnn K said...

There was strange weather east of the Cascades in Oregon, too. I was heading west on I-84 from Idaho on Saturday afternoon and hit snow, wind and low visibility in the Wallowas between Baker City and Pendleton.

Decided some strange weather pattern was afoot and rather than retrace my route home on I-82 via Yakima and the open spaces of eastern WA, I headed for the Columbia and a route home thru Portland. The clouds broke east of The Dalles and it was a beautiful sunset drive with lots of color. Dry roads all the way back to Seattle that evening, a plus.

mainstreeter said...

On This Day, October 07, In 1987, Seattle, Washington Received Four Inches Of Rain In 24 Hours, Setting A Record For The City On This Date.

mainstreeter said...

Parts of E Wa are forecasted to have blowing dust Friday into the evening, then low overnight minimums.

.DAY ONE...TODAY AND TONIGHT

A STRONG ARCTIC COLD FRONT WILL TRACK ACROSS THE CONTINENTAL
DIVIDE LATE TONIGHT. THIS COLD FRONT WILL BE ACCOMPANIED BY STRONG
NORTH TO NORTHEAST WINDS OF 20 TO 25 MPH WITH HIGHER GUSTS. THE
WINDS WILL LIKELY PRODUCE AREAS OF BLOWING DUST AND LOW
VISIBILITIES ACROSS PORTIONS OF THE PALOUSE...COLUMBIA BASIN AND
WATERVILLE PLATEAU. THE MOST WIDESPREAD DUST IS EXPECTED TO OCCUR
WEST OF A LINE FROM DAVENPORT TO ST JOHN.


.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

BLOWING DUST WILL LIKELY CONTINUE TO IMPACT THE AREA THROUGH EARLY
FRIDAY MORNING. THE WINDS WILL DECREASE BY FRIDAY AFTERNOON AND
THEN THE MAJOR CONCERN WILL SHIFT TO THE RECORD COLD ARCTIC
AIRMASS. FRIGID TEMPERATURES...MORE COMMON FOR EARLY
NOVEMBER...WILL INVADE THE AREA AND PERSIST THROUGH THE WEEKEND.
HIGH TEMPERATURES BEGINNING FRIDAY AND LINGERING THROUGH SUNDAY
WILL GENERALLY CLIMB ONLY INTO THE 40S...WITH LOWS IN THE TEENS
AND LOWER 20S. THESE TEMPERATURES ARE AROUND 20 TO 25 DEGREES
BELOW NORMALS AND WILL RESULT IN NUMEROUS RECORDS BEING SET.

Must read blogs said...

its supposed to be 28 friday and sat night