Early morning a few days ago I ventured onto the icy section road to take Angie the History Dog for her morning constitutional and was delighted to feel a warm breeze supplanting the icy gales of the recent cold snap. Returning to my desk, I commenced checking weather reports for Dickinson, Billings, Belle Fourche, and such points west to confirm what I suspected: that at my home in Cass County, we were the beneficiary of a chinook. In the Red River Valley we seldom get a chinook wind with force, but we are grateful when a remnant arrives, spent but still warming.
Otherwise, when temperatures in the west take a welcome turn upward in January or February, we on the east coast refer with mocking envy to Dickinson as “the banana belt.” Chinook bragging rights, however, go to Spearfish, South Dakota, where on 22 January 1943, the temperature rose in two minutes from -4o F. to 45o above, a rise of 49 degrees. Spearfish still remembers this salubrious event with an annual January festival, Chinook Days.
That January day in the Black Hills is deemed legitimately historic because it was investigated and written up by an official authority—one Roland R. Hamann, Weather Observer of the US Weather Bureau. “Weather Observer” is an interesting job. As best I can determine, a Weather Observer is a staff meteorologist who, when some remarkable weather event takes place, is sent out, or sends assistants, to investigate what has happened and document it for the record.
Hamann’s documentation of the chinook of 22 January 1943 is in the Monthly Weather Review, March 1943. “This region is habitually subject to surprising temperature changes,” Hamann observes. “Indeed, the chinook is so prevalent that it may be considered a prominent climatological factor ... Because of such temperature variations this region has achieved some measure of fame, or notoriety, but even these precedents were inadequate preparation for the occurrences of January 22, 1943.”
The “notoriety” mentioned by Hamann is also a matter of official record courtesy of an Assistant Weather Observer a generation earlier, Alvin T. Burrows. His bulletin, “The Chinook Winds,” is in both the Journal of Geography and the US Department of Agriculture Yearbook of 1903. The chinook wind is “peculiar,” says Burrows.
In the dead of winter it blows down from the mountains and high plateaus, where ice and snow are supposed to predominate, as a hot, dry wind upon the foothills and valleys below. Its effects are striking. The snow at these lower elevations, at first blown hither and thither by this increasing wind velocity, soon becomes moist and heavy under the influence of the blasts of hot air, and in an incredibly short time may entirely disappear. The temperature rises with astonishing rapidity and the whole aspect of nature is transformed.
As I read that out loud, I sense the wonder in the weather observer’s voice. Burrows goes on to explain the “Beneficial Influence of Chinook Winds.” After collecting testimony from stockmen along the front range, Burrows concludes,
Were it not for the visitations of this warm, dry wind the vast stock ranges of Montana, Wyoming and the Dakotas would have to be abandoned in the winter, as the cattle and other stock, prevented by the snow from securing access to the nutritious grasses on the plains, would not be able to secure nourishment sufficient to sustain life.
Thus the weather observer credits the chinook for the historic possibility of the range cattle industry on the northern plains. By the way, I have read this essay to Angie the History Dog, and she approves.
