Meanwhile, Portland coated its streets with 2,000 gallons of liquid anti-icer while officials in Oregon and Idaho opened emergency shelters to prepare for a punishing mix of snow and ice starting Thursday.

Southern California could see as much as 6 inches (about 15 centimeters) of rain in the mountains and 3 inches (about 7.6 centimeters) in coastal areas and valleys, according to Brent Bower, hydrologist with the National Weather Service. Strong wind gusts could bring down trees, cause power outages and delay flights.

Evacuation warnings were issued in Mandeville Canyon and other areas ravaged by the Palisades Fire, the most destructive fire in Los Angeles city history, over concerns about potential debris flows during the upcoming storm. There were also warnings for Trabuco Canyon and other areas near the burn scar for the Airport Fire.

All Malibu schools were closed Thursday and the Knott’s Berry Farm shuttered early Wednesday due to the atmospheric river, a long band of water vapor that can transport moisture from the tropics to more northern areas.

Daniel Swain, a climate scientist for the University of California Agriculture and Natural Resources, said the area is in desperate need of rain but this may come too hard and fast. The result could be debris flows and flash flooding around wildfire burn areas.

These burned areas are more at risk to debris flows because vegetation that helps to keep soil anchored has been burned away and loose debris, including ash, soil and rocks, have been added, he said in a statement.

County officials said roads may be closed and urged residents to be prepared should a mandatory evacuation order become necessary.

The rain follows storms Wednesday that dumped heavy snow and freezing rain on a swath of the U.S. East from Kentucky to the nation’s capital, causing hundreds of traffic accidents, knocking out power in places and threatening to flood waterways.

The storm system, which cut a path from Kentucky to Maryland and points farther north on Tuesday, brought more than 14 inches (37 centimeters) of snow to Iron Gate, a tiny Appalachian town in western Virginia, and 12 inches to White Sulphur Springs, West Virginia, a small city about 65 miles (105 kilometers) to the west, the National Weather Service said.

By early Thursday more than 150,000 customers in Virginia and more than 13,000 in North Carolina were still without electricity, according to PowerOutage.us. Appalachian Power, which serves a million customers in West Virginia, Virginia and Tennessee, said more than 5,700 workers were trying to restore power.

The region’s airports received several inches of snow, according to Scott Kleebauer, a meteorologist with the weather service’s Weather Prediction Center.

Nearly 7,000 flights were canceled or delayed across the United States Wednesday, including almost 300 into Ronald Reagan National Airport near Washington, according to the flight-tracking site FlightAware.com.

Hundreds of accidents

In Kentucky, snowy roads caused a head-on fatal crash Tuesday in Nelson County, south of Louisville. The driver of a car lost control going into a curve, crossed the center line and hit an oncoming semi truck head on, according to the county’s emergency management director, Brad Metcalf. The driver died at the scene.

In Virginia, where Gov. Glenn Youngkin declared a state of emergency, the state police reported about 850 crashes on Tuesday and Wednesday, dozens of which involved injuries. Officials said it was not known if they were caused by the weather.

Maryland State Police reported 235 crashes and 185 inoperable or unattended vehicles.

In southern West Virginia, multiple crashes temporarily shut down several major highways Tuesday.

Pacific Northwest Ice Storm

Freezing rain and snow were expected in northwest Oregon and Southwest Washington, which could cause power outages, according to the National Weather Service.

Officials in Oregon’s Multnomah County extended a state of emergency through at least Thursday and said six emergency shelters would be open. Officials said 356 people went to the shelters Tuesday night. Wind chill readings could dip to 10 degrees (minus 12 Celsius) in Portland, the weather service said.

In Idaho, a cold weather advisory was in effect, with wind chills potentially as low as minus 13 degrees Fahrenheit (about minus 25 degrees Celsius) in the north central part of the state.

An ice storm forecast for the Portland area early Thursday and Friday could challenge deliveries of flowers and other gifts for Valentine’s Day. Temperatures plummeted earlier this week in Portland, which is more known for its rainfall.

Julia Duncan, a co-owner of Flowers in Flight, shrugged off the weather, saying the area endured ice storms in past winters and customers are willing to go the extra mile for the people they love.

“It’s Valentine’s Day!” Duncan said. “We’ll just have to wait and see what happens.”

“We’re in the neighborhood where a lot of people tend to do pickups, too, and (we’ve) got a couple of drivers who are willing to drive in the ice and snow,” Duncan said. “So hopefully it won’t affect us too much.”