(Reuters) -A major winter storm pounded the heart of the United States on Tuesday, bringing heavy snow and freezing rain to the Northern Plains and spawning thunderstorms and destructive tornadoes in the South.
The National Weather Service issued tornado warnings across parts of Louisiana, Oklahoma and Texas and said that spotters had confirmed twisters near Grapevine, Texas and west of Shreveport, Louisiana.
The tornado that touched down near Grapevine damaged several buildings and caused traffic accidents in Wise, Parker and Jack counties, the Fort Worth Star-Telegram reported. There were no immediate reports of deaths or injuries.
"You are in a life-threatening situation. Flying debris may be deadly to those caught without shelter. Mobile homes will be destroyed. Considerable damage to homes, businesses, and vehicles is likely and complete destruction is possible," the National Weather Service (NWS) said in a warning issued at 3:45 p.m. central time.
The storm was blamed for the cancellation of more than 70 flights and delay of nearly 800 others as of Tuesday afternoon, Flightaware.com reported on its Misery Map.
"This storm system will continue to produce numerous, widespread, and impactful weather hazards from the Rockies to the East Coast," the service said in its forecast.
Blizzard-like conditions prompted school districts to cancel classes across the Dakotas, Colorado and Nebraska. Some spots in the four-state area were expecting two feet (61 cm) of snow and winds of 60 miles per hour (97 kmph) throughout the next two days, the NWS said.
Blowing snow and ice accumulation forced the closure of many highways and roadways, transportation officials said, urging residents to stay home.
"Be aware of rapidly changing conditions. Reduce speeds and drive according to the conditions," the North Dakota Department of Transportation said on Twitter.
Forecasters warned that temperatures could drop as low as minus 20 Fahrenheit (minus 29 degrees Celsius) across the region, a level that causes frostbite on exposed skin within 30 minutes.
The wintry mix of precipitation will spread from the Upper Great Lakes on Tuesday into the Northeast late on Wednesday, bringing with it the possibility of as much as 8 inches (20 cm) of snow to some spots.