Severe storms overnight in Nebraska, Texas and Ohio damaged homes and tossed rail cars as well as at least one tractor-trailer, and the threat continued Monday with a large part of the central U.S. on alert.
The greatest damage overnight was just outside North Platte, Neb., where two confirmed tornadoes tore roofs off several homes, downed power lines and injured two people.
One twister crossed Interstate 80, flipping a tractor-trailer in its path. The truck's driver was hospitalized.
A rail yard also was hit, with 15 cars derailed or knocked over, the North Platte Telegraph reported. One worker there was hit by flying debris, treated at a hospital and then released.
In central Ohio, tornado sirens went off as large hail and high winds swept through Sunday night. In Gardendale, Texas, two people were hurt when high winds flipped over their mobile home. No tornadoes were reported in either state.
The mix of warm weather in recent weeks with cold pockets across the Midwest and central U.S. has led to an early start to the tornado season.
"It has been an active season already for tornadoes, and that's part of the reason we've scooched up our siren testing starting in March," Paul Johnson, emergency manager for Douglas County in North Dakota, told KETV.
Tornadoes were only part of the recent national weather scene: so too is record warmth and Southwest snow. TODAY's Al Roker reports.
Tornado watches have been issued for parts of Texas and Oklahoma for Monday, while the rest of the central U.S. is under severe weather warnings that include the possibility of large hail and high winds.
The threat will shift slightly to the east on Tuesday, weather.com reported, with parts of Illinois, Arkansas, Louisiana and Texas seeing the biggest threat.
Chicago saw several days of record-breaking 80 degree weather, and in Atlanta, Ga., pollen counts are setting records as well. But in Flagstaff, Ariz., the city is digging out of its second largest snowstorm. Weather Channel meteorologist Mike Seidel reports.
More content from msnbc.com and NBC News:
- Fuhgeddaboutit! NJ top state for fighting corruption
- Soldier held in Afghan killings had financial issues
- Tea Party spokesman arrested in sex assault case
- NYC building's floor collapses during party
- Occupy Wall Street activists return to park, get arrested