TRR classroom

Since the fires in San Diego are the lead news story today, I thought it'd be appropriate to learn what exactly are the Santa Ana winds. My only knowledge of them was from the Steely Dan song, Babylon Sisters, "Here come those Santa Ana winds again". Here's all you need to know...

Santa Anas occur as the result of air pressure buildup in the high-altitude Great Basin between the Sierra Nevada and the Rocky Mountains. This high energy wind spills out of the Great Basin and is pulled by gravity into the surrounding lowlands. The air circulates clockwise around the high pressure area bringing winds from the east and northeast to Southern California. Santa Ana winds get their name from the Santa Ana Mountains in Orange County, the Santa Ana River or Santa Ana Canyon, along which the winds are particularly strong. ---Wikipedia

The reason the winds fuel wild fires is because they are so dry and hot. As the air is forced up in altitude along the mountains, it cools adiabatically, releasing much of it's moisture. Then as it rushes downward toward the coast, it gets compressed thus heating and releasing still more moisture. The relative humidity of Santa Ana air is typically in the single digits which removes moisture from soil and plant matter transpirationally, making it ideal fuel for fire.

There are many pop-cultural references to the Santa Ana winds too. This is one of my favs...

Those hot dry winds that come down through the mountain passes and curl your hair and make your nerves jump and your skin itch. On nights like that every booze party ends in a fight. Meek little wives feel the edge of the carving knife and study their husbands' necks. Anything can happen.”

—Raymond Chandler, "Red Wind"