‘Atmospheric River’ Triggers Flash Floods Across California

A man wades through a flooded street in the Rio Del Mar neighborhood of Aptos, Calif., on Jan. 9, 2023. (Nic Coury/AP Photo)

Another Pacific storm unleashed more heavy rains and damaging winds across California on Tuesday after thousands of people were evacuated due to mudslide and flood risks.

An “atmospheric river event lingers into California with significant impacts from heavy rain, mountain snow, strong winds, and a few severe thunderstorms,” said the National Weather Service (NWS) on Tuesday. “From widespread flooding, rapid water rises, mudslides, landslides with possible debris flows and heavy snow load on structures will persist through today.”

“The core of the system will slam onshore with moderate to heavy rain resuming across much of California today through tonight while several more feet of snow is possible along the Sierra Nevada. Nearly all of California has seen much above average rainfall totals over the past several weeks, with totals 400-600 percent above average values,” said the agency.

Some 90 percent of Californians were under some form of flood watch as of Monday, according to reports.

“Expect widespread power outages, downed trees and difficult driving conditions,” the NWS in Sacramento wrote on Twitter. “Now is the time to prepare if you have not already!”

Because of prior heavy rains, the soil has become saturated and river levels remain high, according to the NWS. The rain that’s slated to fall Tuesday will exacerbate ongoing flooding at several rivers across the state.

The NWS’s river flood monitoring website shows a number of rivers across California at flood stage or nearing flood stage. The treacherous weather, expected to dump as much as 7 inches of rain in some parts by Wednesday, could produce widespread flooding, rapid rises in water levels, mudslides and landslides, especially in areas where the ground has been saturated from previous heavy rainfall, the service warned.

A drone view of a tree that fell during a winter storm with high winds in Sacramento, Calif. on Jan. 8, 2023. (Fred Greaves/Reuters)

A cleaning crew walks through floodwaters in the Rio Del Mar neighborhood of Aptos, California, on Jan. 9, 2023, amid widespread flooding across the state. (Nic Coury/AP Photo)

“By later tonight, the storm system will push rapidly inland, bringing widespread mountain snows across the Great Basin as the heavy precipitation across California begins to wind down. However, an enormous cyclone forming well off the coast of the North American continent will bring yet another Atmospheric River toward the West Coast—this time impacting areas further north from northern California northward up the coast of the Pacific Northwest on Wednesday,” the bulletin added.

On Monday and Tuesday, high winds wreaked havoc on the power grid, knocking out electricity to tens of thousands of Californians. As many as 220,000 homes and businesses were without electricity on Tuesday morning, according to data from Poweroutage.us.

The weather service’s forecast comes after the evacuation of some 25,000 people, including the entire picturesque town Montecito, an affluent coastal enclave 90 miles northwest of Los Angeles, and nearby areas of the Santa Barbara coast, due to heightened flood and mudslide risks.

The Montecito evacuation zone was among 17 California regions where authorities worry the ongoing torrential downpours could unleash lethal cascades of mud, boulders, and other debris in hillsides stripped bare of vegetation by past wildfires.

At least a dozen fatalities have been attributed to several back-to-back storms that have lashed California since Dec. 26, including a toddler killed when a redwood tree was blown over his family’s trailer home last week.

California state highway officials told The Associated Press on Monday that parts of state and U.S. highways were shut down due to mudslides, flooding, heavy snow, or rockslides. That included the northbound lanes of U.S. 101, a key route along the California Pacific coast, as well as U.S. Route 6 and State Route 168.

Gov. Gavin Newsom, a Democrat, requested President Joe Biden issue an emergency declaration to support the state’s response to the wave of storms. That request was granted by Biden on Monday, allowing more resources to be sent to the state via the Federal Emergency Management Agency (FEMA).

“We are in the middle of a deadly barrage of winter storms—and California is using every resource at its disposal to protect lives and limit damage,” said Newsom in a statement. “We are taking the threat from these storms seriously, and want to make sure that Californians stay vigilant as more storms head our way.”

Reuters contributed to this report.