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.

Rows of cars at a dealership, blasted by flames, looked like they had been bombed. A man wearing a mask walked by debris of a neighborhood destroyed. A couple, arms around each other, looked at what was left of their smoldering home. A statue of a human, without a head, lay on a street.