Lingering Atmospheric River Soaks California, Raising Threat of More Flooding and Mudslides

By Steve Gorman and Jane Ross

LOS ANGELES – A severe atmospheric river storm continued to impact Southern California for a third consecutive day on Tuesday, bringing heavy rainfall that raised concerns over potential flooding and mudslides as the weather system moved toward the Desert Southwest.

Following a day of record-setting rainfall, a flood watch in Los Angeles County was extended until early Wednesday. A flash-flood warning was issued for the Orange County coast, while flood advisories spread south to San Diego and the U.S.-Mexico border.

Forecasters predict one last, albeit brief, surge of heavy rain on Wednesday afternoon and evening before conditions begin to improve by the week’s end.

As rain fell across Los Angeles, cleanup efforts were underway following reports of 475 mudslides and nearly 400 fallen trees throughout the city. Downed trees and utility lines left hundreds of thousands without power, including approximately 156,000 utility customers in Los Angeles still without electricity by Tuesday morning. Most had their service restored by nightfall, according to city officials.

Los Angeles Fire Chief Kristin Crowley indicated that at least three dozen buildings required inspections due to mudslide damage and failures of hillside slopes, with seven designated unsafe for occupancy.

"Even if the rain eases a bit today, this storm is ongoing, and we still need residents to take precautions," stated Mayor Karen Bass during a news conference.

Barry Blocker, a 55-year-old retired police officer, recounted spending hours digging his car out from mud that cascaded down a hillside onto his driveway before sunrise. Fortunately, the home he has lived in for 23 years in L.A.’s Baldwin Hills district remained undamaged. "Hopefully, it’s a once-in-a-lifetime scenario," he remarked on Tuesday while cleaning up water and debris from his garage.

Prolonged downpours in the area have delivered 6 to 12 inches of rain citywide, and over a foot in the Hollywood Hills, saturating the ground to a point where even minimal additional rainfall could trigger further landslides and debris flows, according to Ariel Cohen, chief forecaster for the National Weather Service’s Los Angeles office.

The intense rainfall, caused by heavy snow in the mountains, was attributed to an atmospheric river—a vast current of dense moisture drawn in from the Pacific. The recent storm, along with a weaker one that impacted California the previous week, was classified as a "Pineapple Express," originating from subtropical waters near Hawaii.

While such storms occur frequently on the West Coast, meteorologists warn that they are expected to grow more intense and frequent over the next century if human-induced climate change continues to progress at its current pace. The prevailing El Niño weather pattern is also contributing to the recent storm activities along the Pacific coast.

"We can’t say that El Niño caused this storm, but a strong El Niño event like this one definitely facilitates the atmosphere to produce conditions favorable for such systems," explained Daniel Swain, a climate scientist and meteorologist at UCLA.

Swain noted that another factor enhancing the storm’s intensity was the rapid strengthening of the low-pressure system driving it, reaching "bombogenesis" status as it made landfall in Northern California.

The intense storm began in California with powerful winds reaching speeds of up to 75 miles per hour, spreading southward into Southern California early on Sunday. At least three fatalities were reported when strong winds toppled trees in Sacramento, Santa Cruz, and Sutter counties.

In the days to follow, flash floods led to numerous street closures throughout Southern California, and police recorded dozens of traffic accidents linked to the storm. Several neighborhoods particularly at risk for landslides were placed under evacuation orders and warnings.

As showers began to diminish over the Los Angeles and San Diego areas on Tuesday, forecasts indicated increased precipitation for the California desert and Colorado River Basin as the storm front drifted toward Arizona.

Meteorologists have recorded this storm as one of the wettest in over 150 years for Los Angeles.