The Palisades, Eaton and Hurst fires are threatening homes, as strong winds, low humidity and dry vegetation help the blazes spread, fire officials said.

Fire and wind conditions have closed several freeways and highways in impacted Southern California areas. Caltrans provided a list of fully closed highways and freeways, as of Wednesday morning. Closures are due to Palisades,

The Santa Ana winds occur when there is high pressure to the east, in the Great Basin, and a low-pressure system off the coast. Air masses move from high pressure to low pressure, and the more extreme the difference in the pressure, the faster the winds blow. Topography also plays a role.

Kelly Curran breaks down the forecast for damaging winds in Southern California on Tuesday. This forecast is from Jan. 7 at 6 a.m.

While the cause of each blaze has yet to be determined, all burned in or near foothill communities amid gusty winds and dry air and vegetation.