When the air is warm and dry, transpiration and evaporation also suck water out of the plants and soil. That leaves dry vegetation that can provide fuel for flying embers to spread wildfires, as the Los Angeles area saw in early January.

Firefighters have made progress battling some of the blazes. The Palisades Fire is 6% contained after scorching nearly 20,000 acres, and firefighters have made progress tackling two others, the Hurst Fire (37% contained) and the Lidia Fire (75%) contained.