Major storms from Colorado to the Plains spawned giant hail, flash flooding, and tornadoes.
Flooding closed down highways in both Ohio and Pennsylvania, but not before some motorists were trapped by the deep water.
"I can't even go home," Ohio resident Elvia Berrios said. "I was thinking about going back to work. There's no way out, everywhere you look the water is high."
"I've got a book in the car, if I have to be here a couple hours, I'll just be here," another stranded traveler said.
In the Denver area, more than an inch of golf-ball sized hail had cars sliding and people running for cover.
The hail shut down the Denver International Airport after some planes were damaged. Snow plows had to come out to clear the runways.
Tonight, Denver is once again in the bullseye. New York City, Philadelphia, and Washington, D.C., are also in the path of storms that could turn severe.
Authorities warn early holiday travelers to stay alert and check the forecast as they go into the weekend.