CNN WIRE — Atmospheric river parks over Southern California: VIDEO

Updated: 05 FEB 24 09:46 ET

By Ashley R. Williams, Rob Shackelford and Taylor Romine, CNN

(CNN) — An intense, long-lasting atmospheric river is moving across California — bringing widespread power outages and the potential for mudslides and life-threatening flooding as it dumps heavy rain and snow. This is what’s happening:

• Rare high flood risk persists: A firehose of rain has parked over Southern California, including Los Angeles, worsening the high risk of flooding throughout Monday. Torrential rainfall and “locally catastrophic” flooding is possible in Orange County through Tuesday, according to the National Weather Service office in San Diego.

• Power outage numbers remain high: Strong winds and rain have knocked out power for more than 500,000 customers in California, particularly along the coast, according to the tracking website PowerOutage.us. The majority of outages are across the northern half of the state where winds gusted as high as 100 mph over the past day.

• At least one fatality reported: A man in Yuba City, about 40 miles north of Sacramento, was killed Sunday by a large redwood tree that fell as winds of nearly 50 miles per hour hit the area. “Through the investigation, it appeared he was possibly using a ladder to try and clear the tree away from his residence when it fell on him,” the Yuba City Police Department said in a statement. The man’s identity has not been released.

• Los Angeles sees wettest day in 20 years: The torrential downpour brought an astonishing 4.10 inches of rain Sunday to downtown Los Angeles, marking the wettest day the city has seen since 5.55 inches of rain fell on December 28, 2004. February is typically the wettest month of the year in Los Angeles, with an average of 3.64 inches of rain in total downtown.

• Rare rain risk: The Weather Prediction Center issued a rare high risk of excessive rainfall – or a Level 4 of 4 – for more than 14 million people across Southern California on Monday. This includes downtown Los Angeles, Anaheim and Long Beach. In Central and Southern California, widespread rainfall totals of 3 to 6 inches are expected – more than a month’s worth of rain for most areas in several days.

• Life-threatening landslides and flash flooding expected: An “extremely dangerous situation” is unfolding Monday morning in the Hollywood Hills area – where multiple homes have been evacuated – and around the Santa Monica Mountains, the weather service said. “Numerous damaging landslides, flooded roadways, submerged vehicles, and flooded creeks and streams are ongoing,” in an area that includes Malibu, Beverly Hills, Santa Monica, Brentwood and Burbank, the service said.

• Officials enforce evacuation orders: Some residents in Santa Barbara, San José, Los Angeles and Ventura County were under evacuation orders issued over the weekend as officials warned of potential “life-threatening” floods and landslides. Officials went door-to-door on Sunday giving evacuation warnings in Sun Valley, California, according to CNN affiliate KABC. Authorities evacuated residents near Mission Creek in Santa Barbara as water flooded the streets on Sunday.

• Storm hinders travel in the mountains: Significant snowfall totals are expected in eastern California and along Nevada’s border, with heavy and wet snow spreading across the Sierra Nevada through Monday, with accumulation rates of 2 to 3 inches per hour, according to the weather service. Dangerous wind gusts are expected to produce whiteout conditions, making travel above 5,000-6,000 feet “near impossible,” the weather service said.

• Schools cancel classes and go remote: Several school districts in Santa Barbara County have canceled classes on Monday due to the severe weather, while others including California State University Fullerton switched to remote learning.

Atmospheric river continues slamming California

This atmospheric river – a long, narrow moisture band that carries saturated air thousands of miles then discharges it like a fire hose – impacting California this week follows another recent storm that drenched most of the state, including Los Angeles, with record rainfall.

The strongest winds associated with the system have subsided, but there are still gusts up to 50 mph across the higher elevations of Central and Southern California. Wind advisories are in place across Central California and in Orange and San Diego counties Monday morning.

As the state braced for flooded roadways and swollen rivers, Gov. Gavin Newsom on Sunday declared a state of emergency for Los Angeles, Orange, Riverside, San Bernardino, San Diego, San Luis Obispo, Santa Barbara and Ventura counties.

Southern California continued to prep for the prolonged impacts of the storm, which stalled as it moved onshore, bringing a much longer duration of rain compared to the last storm. Californians can expect to see the worst of the storm’s impacts and the heightened flood risk through Tuesday, according to the weather service.

In Los Angeles, officials urged residents to stay off the roads and remain at home if possible – even sending a flash flood emergency alert to phones Sunday evening telling people not to travel due to the “dangerous and life-threatening situation.” All lanes of Interstate 5 were flooded in San Fernando in Los Angeles County as of late Sunday evening. A flash flood warning in place for western and central Los Angeles County covers nearly 4 million people.

Further south, weather service reports showed the storm system “has the potential to drop a significant and unusual amount of rainfall on San Diego,” Mayor Todd Gloria said during a news conference Sunday.

Low-lying and flood-prone areas of San Diego were issued an evacuation warning, according to Gloria. The city will likely see somewhere between 2 to 2.5 inches of rain through Tuesday, with some areas potentially getting half an inch of rain per hour, he said.

“I understand the weariness that comes from these repeated warnings,” Gloria said. “I recognize that fatigue may be settling in, but I can assure you, this decision to issue this warning is not taken lightly.”

In Ventura County, the storm’s dangers began taking shape on Sunday after law enforcement reported several flooded roads, submerged vehicles, rock and mudslides and quickly rising river levels, according to the weather service.

“Life-threatening landslides and additional flash flooding” were expected in the Hollywood Hills area and around the Santa Monica Mountains, the weather service said. The areas have received widespread rainfall totals over 5 inches over the past 24 hours, with some spots topping 9 inches, the weather service in Los Angeles said. Both locations are under a “particularly dangerous situation” flash flood warning early Monday as rain continues to fall, with up to 3 additional inches possible.

In the Los Angeles neighborhood of Studio City, two homes were seriously damaged by a debris flow Sunday night, the Los Angeles Fire Department said. No one was injured, but nine homes were evacuated, fire officials said.

In a separate alert early Monday morning, the department said at least three homes had been impacted by a debris flow in Encino, though only one was occupied at the time. Two people were evacuated and no injures were reported, the department added.

Debris flows are “fast-moving landslides” that destroy objects, and can occur during periods of intense rainfall, according to the U.S. Geological Survey.

In San Bernardino County, three people were rescued after becoming stranded in a tree while trying to cross a flooded road in their vehicle, the San Bernardino County Fire Department said on X Monday morning.

The vehicle became submerged in “rapid flood waters” in the Devore Heights neighborhood, the department said in an earlier post.

CNN’s Tina Burnside, Nouran Salahieh, Allison Chinchar, Caitlin Kaiser, Sara Tonks and Elisa Raffa contributed to this report.