Weather Blog

Pity poor Bellingham

Pity poor Bellingham
You might think it's cold and icy here in the Puget Sound region, but imagine it being several degrees cooler!

In western Whatcom County, it feels around zero degrees as northeast winds continue to rage. A High Wind Warning is in effect until Monday afternoon for gusts as high as 60 mph. 

In fact, for 25 consecutive hours between 10 a.m. Sunday and 11 a.m. Monday, Bellingham has recorded a gust of 40 mph or higher (streak still active as of this update) and they've had a gust of 30 mph or greater every hour since 6 a.m. Saturday morning.

Combined with temperatures around 20, and that puts the wind chill at around -3 degrees! We normally don't have to deal with the wind chill factor much in the Pacific Northwest, but then again, we don't usually get this cold for this long, either. So in case you're not familiar with it, the wind chill temperature was developed to give people a general idea of how much colder it feels when the wind is blowing. The stronger the wind, the colder the wind chill.

It feels colder when the wind blows because the wind will blow away the layer of warmth that your body produces near the surface of your skin. (Think of it as pulling away your natural blanket).  Note that frostbite on exposed skin can begin to occur within 30 minutes if the wind chill drops below -20, and with in 10 minutes if it gets below -30 in a strong wind.

This also applies to warm-blooded animals, but not to inanimate objects. If it's 40 degrees with a wind chill of 25, water will not freeze.

Here is a chart to compute wind chill. Note for you math majors, the formula to compute it exactly is listed on the bottom of the image:

As for why does the greater Bellingham area get picked on with these strong winds, you can blame mountain topography.

In this current weather pattern, arctic air typically forms, well, in the arctic regions, then slides down south and settles into the British Columbia and Alberta.  Air that is that cold is very dense and creates a huge area of high pressure. (To wit, the central pressure of the arctic high currently sitting in the B.C. interior is 30.83".)

Normally, the Rockies and Canadian Cascades provide a barrier that keeps the arctic air up there, but there's a leak in wall, known as the Fraser River Valley, which stretches from the interior of B.C. to western Whatcom County.

This is like poking a hole in a water balloon -- that conduit that allows arctic air to funnel through the valley and then roar out into the greater Bellingham area (like being at the end of the hose) before spilling out into the rest of Western Washington . When the air pressure is really high over B.C., as it is now, that push of air will be quite strong. 

Any kind of lower pressure off the Washington or Oregon coast can exacerbate the situation as it'll create an even stronger pressure difference.

As for now, it appears this arctic wind will keep going strong all week long, and possibly into next week, as arctic air keeps pouring into the B.C. interior. Bundle up!