Bart_Adrian's Blog

You’ve been hearing a lot in the past couple of weeks about the Santa Ana winds driving the wildfires in southern California. The wind coming down the mountain slopes is very warm and dry, because the air is heated by compression as it descends. The rate of heating is 5.5 degrees Fahrenheit per 1,000 feet of descent. In other words, air that is at 60 degrees at the top of a 5,000 foot slope will warm to 87.5 degrees when it descends to the bottom. This warm, dry downslope wind occurs in other parts of the world, but goes by different names. For example, on the east side of the Rocky Mountains it is referred to as the chinook wind. In the European Alps, it is called the foehn wind. And in Argentina, the same wind goes by the name zonda.