‘Dangerous scenario unfolding’ in California from potent storm lashing the entire state

(CNN) — A powerful storm carrying a strong atmospheric river is laying siege to California, where evacuations have been issued because of the risk of life-threatening flooding and debris flows.

“A dangerous scenario is unfolding, with widespread and significant impacts from flash flooding and debris flows expected,” the Weather Prediction Center said about areas near and north of Los Angeles as the downpours arrived Wednesday morning.

More than six flash flood warnings had already been issued in this area of most concern before 7 a.m. PT. “Significant flooding is already occurring,” the National Weather Service said in multiple warnings.

Some areas in the mountains of Ventura County have already seen more than 6 inches of rain.

Feet of mountain snow, severe thunderstorms and strong winds round out the multiple threats the state is facing.

Strong winds and heavy rain were already blasting Northern California this morning, including the Bay Area, where a wind gust up to 108 mph was clocked in the northern hills. Around 140,000 homes and businesses have lost power in the state, according to PowerOutage.us.

Rare high risk on Christmas Eve

A Level 4 of 4 “high” risk of flooding rain is in place for Southern California Wednesday, including more than 7 million people in portions of Los Angeles, San Bernardino, Ventura and Santa Barbara counties, according to the Weather Prediction Center.

These high risk flooding events are incredibly significant: High risks are issued on fewer than 4% of days per year on average, but are responsible for more than 80% of all flood-related damage and 36% of all flood-related deaths, WPC research shows.

Evacuation warnings or orders were in place in parts of at least five Southern California counties, notably around areas recently burned by wildfires.

Rainfall rates could exceed 1 inch per hour at times Wednesday. That’s more than enough to trigger dangerous flash flooding and life-threatening debris flows on recent burn scars, including from January’s Eaton and Palisades fires.

The scorched ground of these scars repels water instead of absorbing it, quickly turning rain into a surge of floodwater that pulls mud and debris with it.

The holiday danger doesn’t end Wednesday: Another atmospheric river-fueled storm will follow Christmas Day and continue into Friday. It’s raising a Level 3 of 4 flooding rain risk for more than 12 million people, including many in Wednesday’s high risk.

All told, rainfall totals in Southern California through the end of the week could be as much as 4 to 7 inches in coastal and valley locations, while foothills and mountains see 6 to 14 inches.

To put those totals into perspective, a city like Los Angeles could see anywhere from two months’ worth of rain to nearly half a year’s worth in just a week.

Residents not evacuating despite orders

Ventura, Santa Barbara, Orange and San Bernardino counties all issued evacuation warnings or orders for the threat of flooding by Tuesday evening. They join orders and warnings first issued on Monday by Los Angeles County for areas in and around burn scars in the greater Los Angeles area, including the Eaton and Palisades fire zones.

The orders in the Los Angeles area for 383 properties that sheriff’s deputies reached out directly to, including going door-to-door, the county Office of Emergency Management said Monday.

But many of the people had chosen not to leave, the city’s Police Chief Jim McDonnell said at a Tuesday news conference.

“I would ask you to seriously reconsider that,” McDonnell said.

They include Steve Schklair and his family, who live in a warning area for debris flow and mudslides, recently moved back into their home in Altadena, which they spent almost a year rebuilding following the fires, he told CNN affiliate KCBS.

But the family will not be evacuating because they live in a “lucky spot” and will instead spend Christmas hunkered down at home, Schklair said.

“All the mud flows — and it does flow — (go) around the house and down the street, never comes up here,” he told KCBS.

Impossible travel conditions in the mountains
Feet of snow falling in the Sierra Nevada will make travel there difficult or impossible at times through Friday. That includes Interstate 80 through Donner Pass.

The heavy snow will be a big change for the region, which has had much less snow than usual to start the season.

If that’s not enough, severe thunderstorms are a threat for coastal parts of California both Wednesday and Thursday. Any storms that turn severe could produce damaging wind gusts or a brief tornado.

Some relief from this nonstop stormy pattern looks to finally arrive for the upcoming weekend.