NASA's Terra satellite captured this eerily beautiful view of Southern California as smoke from the fires is sucked out over the Pacific Ocean by the Santa Ana winds. (3:10 p.m. on October 24, 2007)
The high pressure system over Nevada's Great Basin is weakening, which means the fabled Santa Ana winds - one of many culprits stoking the 23 wildfire fires burning in Southern California - have slowed for the second day in a row.
The Santa Ana winds begin as cold air in Great Basin, a vast desert that covers much of Nevada, and a bit of Utah and Southern California. As the cold air sinks within a high pressure system over the basin, it's forced to move down over the Sierra Nevada range, which compresses and heats the air at a rate of 10C per km (of decent). They then blast toward the Pacific Ocean's cool, low pressure system. In one instance during the last five days, the scalding winds, also called Devil's Breath, reached 111 miles per hour.
There's a common misconception that the winds' heat is generated in the desert, when it's really the sudden compression of cold air. The reason the Santa Ana's are most common from October through March is because of the cool weather from which they spring.
Santa Ana winds - UCLA Dept. of Atmospheric and Oceanic Sciences
NASA images of So. Cal fires
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