Powerful Santa Ana winds are set to pick up again, making it challenging for firefighters to gain control of the severe wildfires in southern California. Meanwhile, a winter storm is bringing cold temperatures,

The winds are common in California in the colder months, but they can sometimes help spread dangerous wildfires.

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.