The Santa Anas fall into the category of katabatic winds.The term essentially refers to a downhill wind. The winds generally form in autumn and winter when temperatures begin to drop in the Great Basin.
http://rss.cnn.com/~r/rss/cnn_tech/~3/174352627/index.html (http://rss.cnn.com/~r/rss/cnn_tech/~3/174352627/index.html).
The Santa Ana winds explained
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