The 55-year-old man was electrocuted after a power line fell Friday afternoon in Van Nuys, Los Angeles police Officer Drake Madison said.
More than 300 flights at Los Angeles global airport have also been cancelled or delayed.
Thousands of Los Angeles County residents remained without power early Saturday, while road crews scrambled to fix sinkholes throughout the area, including one in Studio City that swallowed two vehicles Friday night.
Firefighters rescued one person from the first vehicle, and the driver got out of the second before it fell.
The storm proved to be particularly brutal in the Santa Clarita Valley, where sheriff's officials reported multiple power lines being down, and they warned people not to approach them.
The storm is expected to be the strongest in years.
Ryan Maue, a meteorologist for WeatherBell Analytics, claimed 10 trillion gallons of rain would fall on California in the next week - enough to power Niagara falls for 154 days.
A second person died after a vehicle was submerged by flash flood water in the town of Victorville.
The Los Angeles Fire Department says another tree brought down power lines as it fell on a auto, and a person was hospitalized for possible electric shock.
Southern California bore the brunt of the latest storm to blast into the western United States as the region is now cleaning up from flooding, mudslides, sinkholes and downed trees.
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The pounding rain was accompanied by gusting and powerful winds, which reached up to 70 miles per hour.
A tree fell over, crushing a vehicle in Los Angeles.
A less severe wind advisory, signaling winds of at least 35 mph, will be in effect from 7 a.m.to 7 p.m. Friday in the San Fernando and San Gabriel valleys, L.A. County beach cities, metropolitan L.A., the downtown area and the Hollywood Hills, with east-to-southeast winds of 25 to 35 mph expected in those areas, along with 50 mph gusts.
The Los Angeles Department of Water and Power said around 44,700 of its customers were still without electricity, and Southern California Edison said that as of 6:30 p.m. crews were working to restore power to 6,100 - down from around 80,000 Friday night.
Her leg was scratched by debris and "I was covered in sawdust", she said.
Rainfall totals ranged from 3.5 inches in Santa Barbara to 9 inches in Santa Ynez Mountain Range, and Ojai in Ventura County got 6 inches of rain, the National Weather Service said Friday evening.
Widespread urban roadway flooding is possible, along with flooding in creeks and small streams, and rock and mudslides, especially near canyon roadways.
In San Bernardino County, two lanes remained closed early Saturday after a section of the southbound Interstate-15 Freeway in the Cajon Pass collapsed. A record 1.96 inches fell at Long Beach Airport, breaking the daily rainfall record of 1.81 inches set in 1980.
The California Department of Water Resources, however, said Saturday night that the level of Lake Oroville continues to fall despite the stormy weather, and the amount of water flowing down the spillway continues to be cut. Roads above those elevations may become impassable by late Friday into early Saturday.