A significant storm moved across Southern California Monday, dousing much of the region with light rain overnight and continuing off-and-on through the day, but the forecast of more significant downpours Tuesday has already prompted evacuation orders and warnings due to possible debris flows.
“Light showers today and this evening will turn heavy Tuesday with gusty winds and high elevation snow,” according to the National Weather Service. “… Heavy rain rates are expected in almost all areas at some point Tuesday, though the upslope areas will experience more frequent stronger cells and periods of heavy rain and for that reason a Flash Flood Watch is in effect for the recent burn scars, all of which are in L.A. County.”
Forecasters said coastal and valley areas can expect 1 to 3 inches of rain, with 2 to 5 inches possible in the mountains, with “locally higher amounts.”
A flood watch will be in effect from 10 p.m. Monday through Tuesday evening in the Los Angeles County mountains, Antelope Valley, Santa Clarita Valley and San Gabriel Valley, with forecasters warning of flash flooding, debris flows and rockslides in recent burn scars.
In Orange County, a flash flood watch will be in effect from Tuesday morning through Wednesday morning for the Bond Fire burn area. A flood watch will also be in place for coastal areas Tuesday afternoon through Wednesday morning.
The Orange County Sheriff’s Department announced that a voluntary evacuation order will take effect at 4 a.m. Tuesday for Silverado, Williams and Modjeska canyons in the Bond Fire burn area due to the risk of flooding and debris flows from the storm. County officials urged residents to prepare to evacuate, particularly people with disabilities, transportation difficulties and those with large animals.
An evacuation center will be available from 7 a.m. to 7 p.m. Tuesday at the Norman P. Murray Community and Senior Center, 24932 Veterans Way, Mission Viejo. The Red Cross is expected to offer an overnight shelter at the same location Tuesday night.
The Library of the Canyons will be closed Tuesday due to the order, including the vote center at the library. A full list of other available vote centers is available at www.ocvote.gov.
Much of Orange County will also be under a wind advisory Tuesday, with 20 to 30 mph winds expected, along with isolated gusts up to 45 mph.
Back in Los Angeles County, Duarte city officials said 25 homes in the Fish Fire burn area will be under mandatory evacuation orders beginning at 11 p.m. Monday due to the impending storm and danger of flooding and debris flows. Valley View Elementary School, 237 Mel Canyon Road, will be closed Tuesday, along with various streets near the burn area, including Brookridge Road and Opal Canyon Road, Opal Canyon Road and Mel Canyon Road, Mel Canyon Road at Deerlane Drive, and Mel Canyon Road at Fish Canyon Road.
The Duarte Community Center, 1600 Huntington Drive, will be opened at 11 p.m. Monday as an evacuation center.
Los Angeles County mountains will also be under a winter storm warning from 4 a.m. Tuesday through 10 a.m. Wednesday, although snow is expected to be restricted to higher elevations, with up to 20 inches possible in areas above 7,000 feet. Little to no accumulation is anticipated below 5,000 feet, forecasters said.
Mountaintop winds could reach up to 70 mph, according to the NWS.
The wet weather will be accompanied by chillier days and nights. Daytime temperatures are expected to drop into the low 60s in the valleys and the downtown Los Angeles area Monday through Wednesday, with lows in the 50s Monday and Tuesday and the lower 40s Wednesday, Thursday and Friday.
Wednesday’s highs are only expected to reach 58 in Pasadena and Santa Clarita and 53 in Lancaster.
The Antelope Valley will see overnight temperatures below freezing level later this week, with lows of 33, 30 and 31 degrees expected Wednesday through Friday.
A drying and warming trend is expected by later in the week.