Weather Tidbits: Chinook Wind Formation

This Weather Tidbits deals with how a chinook wind develops. A chinook wind is most common east of the Cascades & the Rockies, which are north to south mountain ranges.  The wind forms as moist, warm air hits the mountain and is forced upwards;  causing the moisture to condense into precipitation. As the air rises it cools, once the cooler air passes over the mountain, it sinks and the air dries and warms as it descends.  Chinook winds can sometimes produce sharp temperature increases over 35°F or more in an hour; along with sharp drops in relative humidity reaching as low as less than 5% producing an extreme fire hazard. The winds are also known for quickly melting snow in the winter.