At least 10 people are believed to be dead -- with the LA County sheriff saying he expects that number to rise -- as a series of devastating fires grow uncontained across Southern California amid dry and windy conditions,

Santa Ana winds in Southern California are often-fierce winds that topple power lines and trees and can turn a spark into a raging wildfire.

By the time the winds get to the point where the Eaton Fire broke out in Altadena on Jan. 7, it’s not uncommon for them to have less than 5 percent relative humidity, meaning essentially no moisture at all.