Although the strongest wind gusts have passed through the Southern California region, another "traditional Santa Ana wind event" will move in Thursday night.

The intense and fast-moving fires that have cut a path of destruction through the suburbs of Los Angeles, killing at least two people, are being driven by the region's powerful Santa Ana winds, with gusts that in some cases surpass hurricane-strength.

Jon Keeley, a research ecologist in California with the U.S. Geological Survey and adjunct professor at UCLA, explains what causes extreme winds like this in Southern California, and why they create such a dangerous fire risk.