What’s a “Chinook”?

After mentioning the Chinook in my last post, I came to realize that outsiders might have no clue as to what the hell that is. Our city’s unofficial slogan is, “Get blown in Lethbridge!”

For your consideration:

Wrecking Ball
Source: http://www.reddit.com/r/funny/comments/1mxrm6/friend_found_a_wrecking_ball/

At first, one might be led to believe that this young gentleman is impersonating Miley Cyrus’ “Wrecking Ball,” however that is not the case! He’s enjoying the dry winds from the west as they bathe his body in warmth. This ball is known as The Lethbridge Wind Gauge, and can be found next to our tourist information bureau on Scenic Drive South.

So, what is a Chinook? Wikipedia explains it quite simply, in plain English:

The Chinook is a foehn wind, a rain shadow wind which results from the subsequent adiabatic warming of air which has dropped most of its moisture on windward slopes (orographic lift). As a consequence of the different adiabatic rates of moist and dry air, the air on the leeward slopes becomes warmer than equivalent elevations on the windward slopes.

As moist winds from the Pacific (also called Chinooks) are forced to rise over the mountains, the moisture in the air is condensed and falls out as precipitation, while the air cools at the moist adiabatic rate of 5°C/1000 m (3.5°F/1000 ft). The dried air then descends on the leeward side of the mountains, warming at the dry adiabatic rate of 10°C/1000m (5.5°F/1000 ft).

The turbulence of the high winds also can prevent the normal nocturnal temperature inversion from forming on the lee side of the slope, allowing night-time temperatures to remain elevated.

And for visual learners, here’s an illustration:


The Chinook is an invaluable wind that keeps our winters moderate and blows all our trash to Coaldale, saving the city millions of dollars. Though, it can be of minor inconvenience, leading to a bad hair day here or there:

In southwestern Alberta, Chinook winds can gust in excess of hurricane force [120 km/h (75 mph)]. On November 19, 1962, an especially powerful Chinook in Lethbridge gusted to 171 km/h (106 mph).

But you don’t have to take my word for it!

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