CHEYENNE, Wyo. – A chilly spring storm was making its way eastward Wednesday after heavy snow and freezing rain prompted hundreds of flight cancellations, stranded motorists and knocked out power to thousands in several Western states.
Officials in South Dakota warned residents to prepare for the worst by staying home and keeping off roads as the system moved through the eastern part of the state.
"We need to hunker down," Sioux Falls Mayor Mike Huether said Tuesday. "This one is going to last a while."
The storm crawled eastward Tuesday night from Colorado and Wyoming, with moderate snowfall forecast overnight from the Dakotas to Wisconsin. Nebraska, where strong winds caused a train derailment in the eastern part of the state earlier in the day, also was expecting more snow.
Freezing rain, low temperatures and strong thunderstorms were forecast elsewhere in the Midwest.
Officials in Wyoming and South Dakota closed portions of major highways as blowing snow decreased visibility and freezing rain made roads treacherous. Up to a foot of snow fell in southwestern North Dakota on Monday, causing several vehicle accidents.
"Spring storms are not unusual, but they can be very dangerous," said Greg Fuller, operations director for the Transportation Department.
April snowstorms aren't unusual in Wyoming and the Rocky Mountain West, but the storm comes after a rather tame winter in many areas. The National Weather Service said Cheyenne's high of 12 degrees Tuesday was the coldest on record for April 9. The previous record was 23 degrees set in 1997.
"I'm pretty confident that this particular storm is more widespread and has caused more travel problems and closures than any storm we've had this calendar year certainly," said Bruce Burrows, spokesman for the Wyoming Department of Transportation.
The storm hit California and Arizona on Monday with strong wind and rain, knocking out power to thousands and kicking up a dusty haze in the metropolitan Phoenix area. It moved into Colorado, where two unconfirmed tornadoes were reported near Akron and strong gusts felled trees and power lines. More than six inches of snow fell at Denver International Airport, where hundreds of flights were cancelled and others were delayed.
Wind rolled a trailer home onto its top and a roof blew off a barn, Washington County undersheriff Jon Stivers said. A motorcycle dealership partially collapsed in Pueblo, Colo., where winds gusted to 64 mph.
In Wyoming's Sweetwater County, gusts up to 71 mph damaged a marina at Flaming Gorge Reservoir and broke windows at the Western Wyoming Community College in Rock Springs, according to the National Weather Service.
In parts of the Dakotas, officials cancelled classes and many local governments closed offices. In South Dakota, Secretary of State Jason Gant said more than two dozen cities and school districts informed him they were delaying elections for a week.
Up to a foot of snow fell in southwestern North Dakota, along with freezing rain and sleet. An oil tanker crashed near South Heart, just south of Interstate 94 west of Dickinson, and spilled what authorities called a minimal amount of oil into the ditch.
Interstate 90 was closed between Rapid City and Sioux Falls, and transportation officials will determine which, if any, stretches can reopen.
Weather Service meteorologist Todd Heitkamp in Sioux Falls said that office had reports of ice accumulations from one-quarter of an inch up to nearly half an inch, leading to power outages and widespread tree damage. As much as 10 to 16 inches of snow was expected north and west of the city.
"That's going to add to the weight of the trees, to the power lines," Heitkamp said. "Then we get the wind on top of that and then we get the snow on top of that. You can envision what can possibly occur."