Saturday, January 25, 2014

Oregon's Fire Season Starts in January and 122 MPH in the Columbia Gorge!

Today brought two extraordinary meteorological events in Oregon:

First, the Oregon wildfire season began in JANUARY, with multiple fires around the state.

Second, winds today gusted up to at least 122 mph at the Vista House in the Columbia Gorge.

This is really unusual.

The National Weather Service has a Red Flag Warming out for the Cascades and Coastal Mountains of Oregon (see graphic).   With drought conditions for the past several months, very strong easterly winds, warm temperatures (reaching to 70F on the central Oregon coast) and rock-bottom relative humidities, western Oregon is ready to burn.  What is a Red Flag Warning?  Here is the official NWS definition:

A RED FLAG WARNING MEANS THAT CRITICAL FIRE WEATHER CONDITIONS
ARE EITHER OCCURRING NOW...OR WILL SHORTLY. A COMBINATION OF
STRONG WINDS...LOW RELATIVE HUMIDITY...AND WARM TEMPERATURES WILL
CREATE EXPLOSIVE FIRE GROWTH POTENTIAL.


And in fact there are now five active fires in the Cascades and three in the coastal mountains (see pictures if fires near Arch Cape).



Take a look at the maximum wind speed during the 24h ending 9 PM on Friday over NW Oregon, lots of gusts reaching 35-45 mph on the coast and the western side of the Gorge had winds hitting 40-100 mph.
:

High temperatures today were in the mid to upper 60s along the Oregon coast.


So combine extraordinary dry condition, warm temperatures and wind and what do you get?  A substantial wildfire danger, even in mid-winter.   And you want to hear about something really strange?  It has been so dry that trees, desperate for water, have been invading and clogging up sewer lines (see image).  A bonanza for plumbers.  This is getting to sound like some kind of horror movie.


Today the pressure difference across the Gorge got to 11 hPa (that is a LOT), with higher pressure in eastern WA.  Plus, there was a pool of shallow cold air over eastern Washington ready to move into the Gorge.  Ideal conditions for gap winds.  Today, the winds gusted to at least 122 mph in the parking lot of the Vista House, which overlooks the Gorge.   In fact, the winds were probably even higher since the unit could not read more than that speed.  On the other hand, it was measured by a hand-held anemometer through a sun roof and thus there was certainly some acceleration of flow around the car.  Here is their proof:


With strong winds over the western Gorge and parts of the Portland Metro area, thousands of folks have lost power around Portland and there has even been structural damage to some buildings (see picture)


But I have some major news.   The weather pattern looks like it will shift on Tuesday and precipitation will return to Oregon and Washington starting early Tuesday. Finally.   And this shift has implications for the Super Bowl on Sunday, Feb 2, as I will talk about in a future blog.

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