At least four people were killed and more than half a million homes were without power after a series of powerful winter storms swept through parts of the eastern United States and Canada.
High winds flipped cars and destroyed homes in Florida, where several tornadoes were reported.
More than 1,300 flights into or out of the United States were canceled Tuesday, according to FlightAware data.
Vice President Kamala Harris' plane had to change course due to weather.
A spokesman for Ms. Harris said that “inclement weather” required her plane from Atlanta to land in Virginia instead of neighboring Maryland on its way back to Washington, D.C.
As of Tuesday evening, more than 630,000 families in the eastern United States, from Florida to New York State, were without electricity.
Florida Governor Ron DeSantis declared a state of emergency in 49 counties in Florida, as storms tore off roofs of homes and destroyed power lines.
Twelve tornadoes were reported across Florida, Alabama and Georgia by early Tuesday, causing extensive damage and, in some areas, prompting search and rescue operations.
More than 22 million people were under hurricane watch.
In Houston County, Alabama, an 81-year-old woman was killed after a tornado struck the area, destroying mobile homes and RVs.
One person was killed and two others were seriously injured in Claremont, North Carolina, after a powerful storm swept through a mobile home park, officials said.
A motorist died in Clayton County, Georgia, after a tree fell on a highway and crushed the driver's car, officials said.
A man was also killed by a falling tree in Birmingham, Alabama, on Tuesday morning, local station WVTM reported, citing local officials.
A resident of Panama City, Florida, who lives across from a house that was toppled by the wind, said the sound sounded like “a freight train hitting a brick wall.”
“That's how loud it was,” he told CBS News, the BBC's US partner.
The storms also left roads impassable in Panama City, ripped off roofs from buildings and brought hailstones the size of baseballs.
A curfew has been declared in the downtown area until 06:00 EST (11:00 GMT) on Wednesday morning.
“No one should be moving in this area after dark,” the Bay County Sheriff's Office posted on Facebook.
The National Weather Service (NWS) warned that more powerful storms were in store for the region and elsewhere in the eastern United States.
- Parts of Florida, Georgia, and North and South Carolina may see more powerful tornadoes, bringing damaging winds and hail.
- Combined with winds of up to 50 mph (80 kph), heavy rains in other parts of the eastern United States could lead to flooding from the Florida Panhandle all the way north into southern Maine.
- In South Carolina, four to five inches of rain fell before sunset on Tuesday, causing flooding in several areas.
- More than a foot of snow has fallen in the US interior, stranding motorists and disrupting the presidential campaign in Iowa.
- In Canada, a winter storm warning extended from southern Ontario, near Windsor, to central Quebec, where more than a foot of snow was also expected.
- A rare powerful snowstorm in the Pacific Northwest downed trees and cut power to more than 25,000 customers in Washington state, according to Poweroutages.us, as well as thousands more north in Canada's British Columbia province. Snow and high winds closed mountain passes, closed ferries and sparked avalanche warnings
In New Jersey, a coastal flood warning is in effect until Wednesday. State Governor Phil Murphy declared a state of emergency and warned residents not to “underestimate” the storm.
In New York State, Governor Kathy Hochul warned that the storm could be “life-threatening,” especially since the expected rainfall will combine with the snow that already covers the ground, leading to potential flash flooding.
Authorities evacuated about 2,000 migrants living in a city shelter tent at an airport in Brooklyn to high school gymnasiums until the storms passed.
A brief ground stop was issued at Chicago's O'Hare International Airport — one of the busiest airports in the country — due to excess snow and ice, the FAA said. A grounding was also issued for Tampa International Airport in Florida due to a hurricane warning.
Severe weather also disrupted ground travel in states like Nebraska and Kansas, where state patrols responded to hundreds of weather-related incidents.
“Please stay home,” a Kansas state trooper wrote on social media. “We're getting to the point where we won't be able to rescue you if you get stuck because we're having trouble getting around.”
The National Weather Service said it expects the severe weather to ease slightly heading into Wednesday, although snow is still possible in some already affected areas in the central United States and the Northeast.
Flood warnings issued by the National Weather Service remained in effect Wednesday morning from Louisiana to Maine, covering at least 15 states along the US Atlantic coast.