Ivy over at The Happy Whisk, was asking me what a Chinook is. Here is the answer to that question, courtesy of wikipedia, along with a picture of a "chinook arch" over downtown Calgary. Click picture to embiggen.
A "Chinook" is a wind from the Pacific ocean flowing over the Rockies into the interior regions of southern Alberta (ie. Calgary and environs). A strong Chinook can melt one foot of snow in a day. The snow partly melts and partly evaporates in the dry wind. Chinook winds have been observed to raise winter temperature, often from below −20°C (−4°F) to as high as 10°C to 20°C (50°F to 68°F) for a few hours or days.
The ch digraph in Chinook is pronounced as in French (i.e., shinook). This is because the French-speaking voyageurs of the fur companies brought the term from the mountains.
In Lethbridge (south of Calgary), Chinook winds can gust in excess of hurricane force (120 km/h or 75 mph). On November 19, 1962, an especially powerful chinook there gusted to 171 km/h (107 mph).
In Pincher Creek (also South of Calgary), the temperature rose by 41°C (from -19°C to 22°C) in one hour in 1962 - trains have been known to be derailed by chinook winds there. During the winter, driving can be treacherous as the wind blows snow across roadways sometimes causing roads to vanish and snowdrifts to pile up higher than 1 meter. Empty semi trucks driving along Highway 3 and other routes in Southern Alberta have been blown over by the high gusts of wind caused by chinooks.
Calgary gets many chinooks - the Bow Valley, in the Canadian Rockies west of Calgary, acts as a natural wind tunnel funneling the chinook winds.