WASHINGTON - A powerful storm with pounding rains and high winds roared up the U.S. East Coast on Monday, threatening travel for millions, after killing at least 20 people in the South and flattening a mobile home park in southwest Georgia.

About 570 U.S. flights were canceled, with Newark Liberty International Airport in New Jersey the hardest-hit U.S. airport. About 10 percent of its flights were canceled, according to the air traffic website FlightAware.

New York City emergency management officials warned winds could reach 60 miles per hour (97 km per hour) through Monday night, with more than 3 inches (7.5 cm) of rain possible. Flood advisories and watches were issued for much of the region.

Roads turn dangerous due to snow

Northern Pennsylvania and parts of New England were expected to get more than 6 inches (15 cm) of wet snow, producing dangerously slick roads. Winds topping 50 mph (80 kph) could whip the East Coast from Delaware to eastern Maine.

The National Weather Service said the front would reach the Middle Atlantic coast by Monday evening. A flood warning was in place for part of southwestern Virginia, and a high wind advisory was put out for western North Carolina.

The rain and snow will ease a dry spell in the northeast United States, where much of the region is suffering from moderate to extreme drought, according to the U.S. Drought Monitor.

Tornadoes and storms killed 15 people over the weekend in Georgia. In Dougherty County, where at least four people died, families were separated and many people left without homes, food or hope, officials said.

Jenny Bullard carries a pair of boots from her hom
Jenny Bullard carries a pair of boots from her home that was damaged by a tornado, Jan. 22, 2017, in Adel, Georgia.

Flash flood warning in California

A mobile home park was particularly hard hit.

“It literally looks like God took half of the mobile home park and threw it across the street into the woods,” Dougherty County Commission Chair Chris Cohilas said at a news conference.

Mississippi reported four dead from a tornado on Saturday, and one death was reported in northern Florida's Columbia County.

Flash flood watches were issued for southern California through late Monday, with hail and thunderstorms forecast after a Pacific storm system dropped 4 inches (10 cm) of rain on Los Angeles over three days, the NWS reported.

The agency said the system would bring heavy snow to the state's Sierra Nevada mountains and then move into the Rocky Mountains. Parts of the mountains have gotten up to 108 inches (270 cm) of snow in the last week.