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.

The UCLA climate scientist warned of the devastating blazes several days before they ignited. He discusses the conditions that prompted his prediction.

The state is seeing a sharp water divide this year, with lots of rain in the north while the south has stayed dry. A hydrologist explains what’s happening.