What are Chinooks?
A Chinook is a warm and dry wind which can lead to a significant temperature change over a region affected by such a wind. Consider air moving eastward from the Pacific Ocean onto the North American continent. As the as the air encounters the mountain ranges, it is forced upward, a process which cools the air. If the air cools enough, condensation can occur and clouds and precipitation can develop. This is why one observes relatively high amounts of precipitation on the western side of the coastal B.C. mountain ranges. The precipitation removes much of the moisture which was originally in the air impinging on the mountains. East of the mountains, the air again descends, and this process warms the air. Therefore, this is warm and dry air and is referred to as a chinook. The same process can occur in other mountain ranges, although the term “chinook” is local to the Rockies.
A Chinook generally refers to a warm and dry wind, sometimes strong, that can lead to a significant temperature rise downwind of the Rocky Mountains in Alberta. Consider air moving eastward from the Pacific Ocean onto the North American continent. As the air encounters the mountain ranges, it is forced upward, a process which cools the air. If the air cools enough, condensation can occur and clouds and precipitation can develop. The precipitation removes much of the moisture which was originally in the air impinging on the mountains. East of the mountains, the air again descends. This descending air warms as it flows down, and the relative humidity decreases. The warm and dry wind is referred to as a Chinook.
