Back-to-back storms in already-soaked California raise flood threat

(CNN) — Two storms, including a long-lived atmospheric river event, will inundate much of California starting this Saturday and into next week, increasing the risk of flooding and landslides.

The state is still recovering from a particularly powerful storm that brought record rainfall and hundreds of mudslides to Los Angeles and other parts of Southern California in early February.

The two storms are not predicted to be as destructive as those in early February, but repeated rounds of rain and the slow pace of the second storm will bring significant flooding risks.

As a result, more than 27 million people are under flood watch, stretching from northern California south to parts of the Los Angeles area.

The first storm is expected to be weaker than the second, but the second storm “will act as a primer, increase soil moisture and swell rivers and streams ahead of Sunday’s heavy rains”, the service said. National Weather Service.

It will move along the Northern California coast early Saturday morning and spend the rest of the day drenching the region with 25 to 50 mm of moderate rain. Only light rain is expected along the Central Coast and southern California.

A strong atmospheric river has its sights set on drenching the California coast this week – CNN Weather

A second, more powerful storm will arrive Sunday afternoon and linger along the coast until early next week, raising the possibility of heavy rain across much of the state by Wednesday.

The northern part of the state will witness the shock weather mainly on Sunday, with 25 to 76 mm of rain expected in low-lying areas and 76 to 127 mm in higher elevations.

“Soils around the Bay Area are near saturation, so rainfall will run off quickly and contribute to numerous shallow landslides in steep areas,” said the National Weather Service office in San Francisco.

There will also be gusty winds, but not as strong as the deadly hurricane-force winds of the early February storm that left millions without power. Wind gusts of 56 to 80 km/h are expected Sunday night into Monday, and “more trees may be down and power may be out,” the San Francisco Forecast Office said.

The heaviest rain will begin to move south Sunday night and early Monday morning, engulfing parts of the Central Coast and southern California. Santa Barbara, in particular, is under a Level 4 flood risk starting Sunday and lasting through Monday night.

On Monday afternoon, heavy rain arrived in Los Angeles, where there is a Level 2 of 4 flood risk Tuesday through early Wednesday.

“Rainfall in the region is likely to reach 0.5 to 1 inch (12 to 25 mm) per hour, with a chance of more than 1 inch (25 mm) per hour,” the meteorologist said. Rainfall totals of 50 to 101 mm are forecast for coastal areas and 101 to 156 mm for higher elevations from Sunday to Wednesday.

The National Weather Service office in Los Angeles said, “This amount of rain totals last week will raise concerns about flooding and mudslides.”

While the coasts will be drenched with significant rain, more snow is forecast at higher elevations.

Saturday’s storm will be the weaker of the two systems in terms of snow accumulation, with 4 to 10 inches of snow expected in the higher elevations of the Sierra Nevada and southern Cascade Mountains by Sunday morning.

“Mount Shasta could easily see two feet of snow on its high terrain Saturday or Saturday night, which could keep some people at the ski park happy,” says the National Weather Service office in Medford, Oregon.

However, that second storm will bring more snow to the region.

For Wednesday, snowfall totals in the Sierra Nevada above 1,676 meters could reach 0.3 to 0.6 meters and the highest peaks could see up to 1.21 meters of snow.

“Mountain travel is strongly discouraged while the warning is in effect, as potential impacts include difficult or impossible travel conditions, snow-covered roads, chain checks, reduced visibility and road closures,” the weather service office warned. National in Sacramento.