Tuesday 15, Dec 2015

Baby, it's cold outside

chinook schem

But that could change at any second in Keystone. With our altitude and the nature of Black Hills weather patterns, we are blessed with the occasional Chinook wind in the middle of winter.

Chinooks can range from a gentle puff of warm air to a rush of heat. They always bring a significant change in temperature.

How significant? Spearfish, to the north of Keystone, has held the world record for temperature change for more than seven decades. On the morning of Jan. 22, 1943, the temperature in Spearfish rose from -4 degrees to +45 degrees in just two minutes. That's a 49-degree change. Drivers had to stop in the middle of the street because their windshields suddenly frosted over.

Most Chinooks are not that drastic, but they are great when they happen. 

The Chinook phenomenon occurs when a strong wind pushes moist air up the slope of a mountain range such as the Black Hills. Friction causes the air to lose its moisture in the form of snow (usually) and heat up. As it rises, the suddenly lighter air picks up speed. When the air reaches the top of the ridge, it follows the down slope into the canyons and valleys and other leeward low points.

Artist Charles M. Russell's famous 1900 painting of a starving cow circled by wolves on a snowy prairie is titled "Waiting for a Chinook .. the last of 5000."

These days, the Chinook wind is not a matter of life and death. It is definitely a pleasant surprise when it happens. And today, we'd welcome a Chinook. ... like right about now.