PIERRE, S.D. —
Dangerous winter weather ravaged the nation from California through the northern Plains on Thursday, trapping drivers on icy roads, knocking out power to hundreds of thousands of households and grounding multiple flights.
For the first time since 1989, the National Weather Service issued a blizzard warning for the mountains of Southern California. Forecasters predicted “multiple rounds of new snowfall,” with accumulations of up to three to five feet for the Sierra Nevada region.
All that moisture in the air also creates an increased risk of flash flooding through Saturday, forecasters said. Some coastal areas could see waves as high as 10 to 14 feet through Thursday, forecasters said.
The series of storms sowed chaos from coast to coast. At one point Wednesday, more than 65 million people in more than two dozen states were under weather alerts. The weather service said temperatures in some parts of the upper Midwest could plunge to 40 degrees below average, while high readings Thursday in the mid-Atlantic and Southeast could reach 40 degrees above average.
The wintry mix hit hard in the northern U.S., closing schools and offices and forcing churches to call off Ash Wednesday services.
In Wyoming, the state Transportation Department posted on social media that roads across much of the southern part of the state were impassable.
Rescuers tried to reach people stranded in vehicles, but high winds and drifting snow created a “near-impossible situation” for them, said Sgt. Jeremy Beck of the Wyoming Highway Patrol.
In the Pacific Northwest, high winds and heavy snow in the Cascade Mountains prevented search teams from reaching the bodies of three climbers killed in an avalanche on Washington’s Colchuck Peak over the weekend.
Heavy snow during the afternoon rush hour Wednesday sent dozens of cars spinning out in Portland, Ore., and caused hours-long traffic jams. The regional bus service offered free rides to warming shelters for homeless people.
In Arizona, several interstates and other highways were closed because of high winds, falling temperatures and blowing snow. The state Department of Transportation advised people not to travel. Forecasters said snow could fall at a rate of two to three inches per hour Thursday.
Electrical grids took a beating as ice encrusted utility lines in the North and gusty winds knocked down lines or fouled them with tree branches and other debris in California.
A half-inch of ice covering a wire “is the equivalent of having a baby grand piano on that single span of wire, so the weight is significant,” explained Matt Paul, executive vice president of distribution operations for Detroit-based DTE Electric.