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."