South Dakota ? A wintry blast of punishing wind and close to 4 feet of snow in places pummeled the Northern Plains on Thursday, stranding unknown numbers of motorists for a day or more and knocking out power to thousands.

State officials said some people could be without power for days, but they had a simple message for anyone thinking of trying to drive in western South Dakota’s blizzard: Don’t.

“This is a dangerous storm,” Gov. Mike Rounds told reporters in a telephone conference call Thursday evening. “Western South Dakota is basically under a no-travel advisory.”

Dozens of schools, agencies, businesses and attractions, including Mount Rushmore National Memorial, were closed because of the weather, which included wind gusts higher than 50 mph.

The storm also closed Interstate 80 in eastern Wyoming and western Nebraska.