That lack of precipitation is one reason fires have exploded across Southern California this week, officials said. Thousands of people were evacuated across Los Angeles County and in the path of another fire in Ventura.

It is too soon to ring any drought alarm bells. Still, the memory of the long, punishing drought that ended last year — the worst in this state’s modern history — remains fresh. And a report earlier this week by the Lawrence Livermore National Laboratory said that atmospheric conditions caused by global warming, including the creation of a resilient, water-blocking atmospheric ridge, means even less rain in the future.

“I still have a drought hangover so I wake up worried about drought,” said Felicia Marcus, the head of the state Water Resources Control Board.

Southern California is dealing with the same collection of forces that accounted for the intensity of the wine country fires: an unusually wet winter led to extensive brush growth and a record-hot October baked the growth into kindling. The final ingredient was the heavy Santa Ana winds whipping across Southern California.

“It was sort of a trifecta for Napa and Sonoma,” Ms. Marcus said. “And now you are seeing that recreated in Southern California.”