At least three people have died and over half a million homes are without power after a series of powerful winter storms swept through parts of the eastern US and Canada.
Strong winds flipped cars and knocked over homes in Florida, where several tornadoes were reported.
More than 1,300 flights in or out of the US were cancelled on Tuesday, according to data from FlightAware.
Vice-president Kamala Harris' plane had to be diverted due to weather.
A spokesperson for Mrs Harris said that "inclement weather" required her plane from Atlanta to land in Virginia rather than Maryland on her way back to Washington DC.
As of Tuesday evening, more than 630,000 households in the eastern US, from Florida to New York State were without electricity.
Dozens of counties in Florida have declared a state of emergency, where storms have blown roofs off homes and knocked down power lines.
Twelve tornadoes were reported across Florida, Alabama and Georgia by early Tuesday, causing significant damage and, in some areas, prompting search and rescue operations.
In Houston County, Alabama, an 81-year-old woman was reportedly killed after a tornado ripped through the area, destroying mobile homes and RVs.
One person was killed in Claremont, North Carolina, officials said, after a powerful storm moved through a mobile home park.
And one motorist died in Clayton County, Georgia, officials said, after a tree fell across a highway and crushed the driver's car.
A resident of Panama City, Florida, who lives across from a home that was toppled by the wind said it sounded like a "freight train hitting a brick wall".
"That's how loud it was," he told CBS News, the OceanNewsUK's US partner.
The storms also left roadways impassable in Panama City, ripped roofs off of buildings and brought hail the size of baseballs.
A curfew has been declared for the city's downtown area until 06:00EST (11:00GMT) on Wednesday morning.
"No one should be moving around in this area after dark," the Bay County Sheriff's Office posted on Facebook.
The National Weather Service (NWS) warned that more powerful storms are in store for the region and elsewhere in the eastern US.
Parts of Florida, Georgia, North and South Carolina may see further strong tornadoes, bringing damaging wind gusts and hail
Along with winds of up to 50 mph (80 kph), heavy rain across other parts of the eastern US could bring flooding from the Florida Panhandle all the way north to southern Maine.
In South Carolina, four to five inches of rain had already fallen before sunset on Tuesday, causing several areas to flood.
More than 1ft of snow fell in the US interior, stranding motorists and interrupting presidential campaigning in Iowa
In Canada, a winter storm warning has stretched from southern Ontario, near Windsor, up to central Quebec, where more than 1ft of snow is also forecast
A powerful rare blizzard in the Pacific Northwest region toppled trees and knocked out electricity for over 25,000 customers in Washington state, according to Poweroutages.us, as well as for thousands more people further north in Canada's British Columbia province. Snow and high winds closed mountain passages, shut down ferries and triggered avalanche warnings
In New Jersey, a coastal flood advisory is in effect until Wednesday.
The state's governor Phil Murphy declared a state of emergency and warned residents not to "underestimate" the storm.
In New York State, Governor Kathy Hochul warned the storm could be "life threatening", especially as the expected rainfall would combine with the snow already blanketing the ground, bringing about potential flash-flooding.
Around 2,000 migrants living in a city tent shelter on an airfield in Brooklyn were evacuated by authorities to high school gymnasiums until the storms pass.
A ground stop was briefly issued at Chicago's O'Hare International Airport - one of the country's busiest - due to excessive snow and ice, the Federal Aviation Administration (FAA) said.
A stop was also issued for Florida's Tampa International Airport due to a tornado warning.
Severe weather has also disrupted road travel in states like Nebraska and Kansas, where state patrol has responded to hundreds of weather-related incidents.
"Please stay home," a Kansas state trooper wrote on social media. "It's getting to the point where we will not be able to rescue you if you get stuck because we are having trouble getting around."
The NWS said it expects the extreme weather to slightly ease going into Wednesday, though snow showers are still possible in some of the already affected areas in the central US and the northeast.
