Saturday, July 19, 2014

Gusting Winds Result In Explosive Fire Growth

During the past few days, several small fires--most initiated by lightning--exploded as winds have surged due to the cooling and increasing pressure west of the Cascades.

In only a few days, one fire has gone from virtually nothing to over 200,000 acres--the Carlton Complex Fire northwest of Lake Chelan.  And the fire near Leavenworth also grew rapidly as winds increased.

To illustrate the wind speed increase, here are the sustained winds (not gusts) at Ellensburg and Wenatchee over the past two weeks.  The last day has been the windiest in a while.


 The max wind during the 24h period ending 9 PM on Frida, shows gust reaching 40-50 mph (ignore the 159 numbers) along the eastern Cascade slopes.


As I noted earlier, the cooling west of the Cascades causes the pressure differences across the mountains to rise (cooler air is more dense and thus weights more), and that contributes to the stronger westerly winds.  Take a look at the forecast pressure map for 11 AM this morning (solid lines are lines of constant pressure, isobars).  You can see the intense pressure gradient across the Washington Cascades.


The good news is that cooler air is moving across the Cascades and the pressure difference is now dropping, which should allow the winds to relax a bit over the weekend.

Global Warming, the Media, and Coal Trains

I will be giving a talk in Friday Harbor and Eastsound, sponsored by the San Juan Island and Orcas Is. libraries.

I will be discussing the serious threat of global warming, how the media is generally doing a poor job in educating about this issue, and how mankind is really not taking it seriously (e.g., the coal trains). 

Friday Harbor: July 22nd, 6:30 PM, The Mullis Community Center, 589 Nash St.

Orcas Island:  July 23rd, 5:30 PM, Orcas Center

2 comments:

Andrew Smith said...

High pressure gradient is bad for forest fires fore sure, but it is the lifeblood of wind-driven water sports like kiting and windsurfing on the Columbia River. We watch the pressure differential between Portland, The Dalles, and Hermiston OR every day to see how much wind will be on the water. This week has been great from that perspective!

Placeholder said...

Hey Cliff, at some point can you update us about La Nina? The latest I've been reading is not even a mild one. What do you think?