A Chinook Wind is a warm, dry wind that descends the eastern slopes of the Rocky Mountains in North America. It occurs when moist air rises over the mountains, cools, and loses moisture as snow or rain. As the air descends, it warms rapidly, leading to a significant temperature increase in a short period. These winds can cause dramatic weather changes, often melting snow and raising temperatures by as much as 20 degrees Fahrenheit in just a few hours. The phenomenon is particularly common in areas like Montana and Colorado, where residents may experience sudden warmth during winter months.