“Katabatic Winds”

by Caleb, KE0FOE

Katabatic winds are caused when a cold air mass flowing from an elevated plateau is forced down to a lower elevation by gravity. These winds are warm and very dry due to compression effects, and they can cause wildfires to spread rapidly.

Known locally as Santa Ana Winds, one of the most common occurrences of katabatic winds in the United States happens in Southern California. During the fall and winter, as cold, dense air from the Great Basin moves toward relatively lower air pressure over the Pacific Ocean, gravity forces this air from elevations of several thousand feet down to sea level.

The weather conditions which are fanning the fires currently burning in northern California are known as Diablo winds. While Diablo winds are technically not katabatic winds, they have the same effect on wildfires near the San Francisco Bay area as the Santa Ana Winds have in Southern California.

Here in southwest Missouri we occasionally feel the effects of katabatic winds which originate from the plateaus of southwestern Texas. During these conditions, we often have above-normal temperatures, low dew points, and high fire danger. In fact, these winds can often aid in the formation of dry lines – a key ingredient for severe weather outbreaks in the spring.

For more interesting facts about Katabatic Winds, visit Wikipedia. Check out this YouTube video showing an extreme Katabatic Wind event in Canada: https://youtu.be/2H8Y5ptn9Cs