Mandatory evacuations are in effect for some Southern California foothill communities as a powerful winter storm that will bring rain, snow, gusty winds and the threat of flooding and mudslides continued to slam the region Friday.
Most of the region is under a flash flood advisory Friday morning as significant rainfall began in West Hollywood, Pasadena, Burbank, Altadena, and Studio City late Thursday night. Rain arrived throughout Southern California early Friday morning with flooded streets reported across a widespread area -- the result of what the National Weather Service described as the “largest rain event” in Southern California since March 2011.
"This is a powerful storm, something we haven’t seen in several years here in Southern California," NBC4 meteorologist Crystal Egger said.
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About one inch of rain fell in downtown Los Angeles by Thursday morning as the result of the first storm. Some of the most significant overnight rainfall totals were reported northwest of Los Angeles in Santa Barbara and Ventura counties.
In San Bernardino County east of Los Angeles, flooding and rockslides were reported in some hillside area. Specially trained swift-water rescue teams were deployed in the Lytle Creek area, where past storms have led to floods and fire-rescue responses.
"Lytle Creek is notorious," said Chis Prater, of the San Bernardino County Fire Department. "There's a creek that runs through town. Not only the creek, but the roads have been notorious for flooding."
The second storm is expected to be much stronger than the first, with heavier rain anticipated Friday and Saturday. Rain is expected through Sunday.
"We anticipate a number of impacts including flooding, mud and debris flows, heavy mountain snow, high winds, dangerous surf and possible tornadoes," Egger said.
Mandatory evacuations are in effect for more than 1,000 homes in the San Gabriel Valley foothill communities of Glendora and Azusa to protect residents from possible mudslides and debris flow, as January’s Colby Fire left the steep mountain slopes bare. The area was under a flood watch early Friday.
A nine-mile stretch of the Pacific Coast Highway in Malibu was closed overnight Friday. The California Highway Patrol implemented the closure -- extended to noon -- because of anticipated rock and mudslides as a result of last year’s Spring Fire.
A spokeswoman for CHP told NBC4 damage from the fire was so severe, officials "expect the mountain to come down."
The National Weather Service issued a flood advisory for Ventura County until 6 a.m. According to the NWS, minor flooding is likely in and below the recent burn areas. A coastal flood advisory is in effect for Los Angeles County through noon Saturday, according the NWS website.
Strong winds and heavy snow is expected in the San Bernardino and Riverside County Mountains Friday evening through Saturday night. Snow levels are expected to drop from around 10,000 feet Friday morning to 6,000 feet by Saturday, according to the NWS.