Fire crews in Los Angeles have gotten a brief reprieve from brutal Santa Ana winds that have been fueling five wildfires. At least three are still raging at zero containment, and nearly 180,00 people are under mandatory evacuation orders,

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.

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.