Los Angeles officials said Tuesday night there had been 475 mudslides since the storms brought rain to the area over the weekend. Thirty-eight buildings now need inspection due to mudslides and slope failures. So far, four buildings have been given no-entry red tags and nine are yellow tagged, which means people can only go into to collect their possessions. The city has also, at its most recent count, a record of 390 fallen trees and branches and 441 potholes. Authorities also said they've cleared 963 catch basis and stormwater conveyance systems.

-ABC News' Marilyn Heck

The heaviest rain is moving south of Los Angeles, toward San Diego, on Tuesday afternoon. By Tuesday night, the heavy rain will reach Arizona.

Flood watches will remain in effect through Tuesday night across Southern California, from Los Angeles to San Diego, as well as in parts of Nevada and Arizona.

A tornado warning has also been issued in the San Diego area.

Through Thursday, an additional 1 to 2 inches of rain is possible in parts of Southern California. With the ground already so saturated, mudslides and flash flooding will remain a threat for much of the week.

-ABC News’ Melissa Griffin

"This storm continues -- and that means we still need Angelenos to take precautions," Los Angeles Mayor Karen Bass warned Tuesday.

Periods of rain will continue Tuesday creating dangerous conditions on the roads and increasing the chance of mudslides and flooding, Los Angeles Fire Department Chief Kristin Crowley said.

No fatalities have been reported in LA, Bass said.

Crews have responded to 307 mudslides and 257 fallen trees, Crowley said.

If you must go outside, use caution, Crowley warned. Slow down if driving and always be on the lookout for downed power lines and trees, she said.

The mayor commended residents who have checked on each other in hard-hit communities and stressed that everyone should check on their neighbors.

The "historic" rain is expected to taper off late Tuesday night, National Weather Service meteorologist Ariel Cohen said.

There’s a chance for more atmospheric rivers this spring, Cohen said.

Downtown Los Angeles recorded 7.03 inches of rain on Sunday and Monday, marking the wettest two days in the city since 1956.

Los Angeles averages 14.25 inches of rain for an entire year. So far this year, LA has recorded nearly 11 inches of rain, or 75% of the city's annual rainfall.

And the rain is still falling. As of Tuesday morning, the three-day rainfall totals have climbed to: 12.2 inches in San Bernardino County; 12 inches in Bel Air in Los Angeles County; 9.4 inches in Santa Barbara County; 8.7 inches in Ventura County and 7.6 inches in downtown Los Angeles.

Evacuation orders and evacuation warnings have been issued in some parts of Los Angeles, Ventura, Santa Barbara and Orange counties as life-threatening flooding hits the region, trapping people in cars and forcing residents to evacuate their homes.

In Los Angeles’ Baldwin Hills neighborhood, about six cars crashed while heading down a hill where the road was partly covered with mudslide debris, according to Los Angeles police. Multiple people were injured and one person might have suffered a broken leg, police said.

In San Bernardino County, three people were trying to drive across a flooded road when the car became submerged, according to the San Bernardino County Fire Department. The three people clung to a tree and were rescued, officials said.

In Los Angeles’ Studio City neighborhood, firefighters rescued 16 residents after debris flow damaged homes, the Los Angeles Fire Department said. No one was injured, officials said.