LOS ANGELES — A powerful storm barreling toward California from the tropical Pacific threatens to trigger widespread river flooding throughout the state as warm rain melts a record accumulation of snowpack and sends runoff surging down mountains and into streams and reservoirs.
Although state officials insist they are prepared to manage runoff from what is now the 10th atmospheric river of a deadly rainy season, at least one expert described the combination of warm rain, epic snowpack and moist soils as "bad news."
"We're expecting rain in the areas where there was snow, and the rain is warm, and it will melt the snow that is already there," said Alistair Hayden, a former division chief at the California Governor's Office of Emergency Services. "So what's going to run into the rivers is not just the rain that's falling from the sky — it's going to unlock some of the precipitation that fell as snow, so it could be big."
