A severe weather system is threatening parts of the South.
GEORGIA - Weekend tornadoes killed at least five people, including three children, in the US South, authorities said on Sunday, as a massive storm system with damaging wind and hail moved across the country and began drenching East Coast states.
A tornado touched down and spun toward Enigma, Georgia, on Sunday, after 17 twisters were reported on Saturday and earlier on Sunday across the South from Texas to Alabama.
"We'll be seeing severe weather from Florida to New York, with the most unstable parts so far in Georgia," said meteorologist David Roth of the National Weather Service (NWS) Weather Prediction Center.
Tornado watches, some lasting through early Monday, were issued for most of West Virginia, most of North Carolina, Virginia, Pennsylvania and Maryland and parts of Ohio and New York. The watches mean conditions are favourable for tornadoes to form.
The affected areas will get heavy rains, winds with gusts of up to 110km/h and the possibility of hail, Roth said.
"Whenever you have a tornado watch, you also have threats for severe thunderstorms," he added.
More than 100 million people from the middle of the United States to the East Coast were at risk of extreme weather, facing warnings of heavy thunderstorms and another round of tornadoes said NWS meteorologist Bob Oravec.
Nearly 2,300 US flights were cancelled by Sunday evening, more then 90 percent of them at airports in Chicago; Houston, Texas; Charlotte, North Carolina; Pittsburgh; Columbus, Ohio and a dozen major airports on the Eastern Seaboard, according to FlightAware.com.
The storm's cold front also brought snow to Chicago on Sunday, with 2.5 to 7.6cm reported in central Illinois.
Soaking rains could snarl the Monday morning commute on the East Coast before the storm moves off to sea.
"The biggest impact rush hour-wise probably will be Boston, around 7 to 8 o'clock in the morning, and around New York City around 5 or 6 o'clock, before sunrise," Oravec said.