Storm brings test for burn scars

'Goldilocks' atmospheric river is first major rain of the water year

- HANNAH FRY, CLARA HARTER AND ALEX WIGGLESWORTH

A PEDESTRIAN runs through rain in Santa Clarita on Tuesday. Showers may linger in the area Wednesday.

MYUNG J. CHUN Los Angeles Times.

An early season atmospheric river that brought powerful winds, heavy downpours, flooding and even tornado warnings to Southern California was also a significant test for the region's burn scars ahead of its traditional rainy season.

The storm — Los Angeles’ first significant rain of the water year that began Oct. 1—dumped 2 inches of rain in Bel-Air and Beverly Hills, 1.15 inches in downtown Los Angeles and 3.28 inches in Woodland Hills as of 11 a.m. Tuesday. The last time downtown got more than an inch of rain in a single day in October was 2009, said John Dumas, a meteorologist with the National Weather Service in Oxnard.

The storm, classified as a weak, or Level 1, atmospheric river, brought enough moisture to Southern California’s drought-stricken landscape to delay fire season for weeks, if not months, said Marty Ralph, director of the Center for Western Weather and Water Extremes at UC San Diego’s Scripps Institution of Oceanography.

And it did so without disintegrating the hills ravaged by January’s Palisades and Eaton fires into large flows of rock, mud and debris, Ralph said.

"In a way this is like a Goldilocks atmospheric river," Ralph said. "It's sort of just right to be mostly beneficial at this stage of the year.”

Officials were most concerned about the burn scars from the January firestorms in Pacific Palisades, Alta-dena, Sylmar and the Hollywood Hills, which were all at high risk of debris flows.

Burned soil repels water instead of soaking it in, so it takes less rain to trigger damaging flooding and debris flows, Dumas said.