Storms Sweep Across Eastern U.S., Killing at Least 2

A “complicated and active” storm system swept across the Eastern United States on Monday evening, delivering widespread thunderstorms that killed at least two people, grounded thousands of flights and left more than a million homes and businesses without power.

The line of storms barreled through a stretch from Georgia to New York, downing power lines, sending trees crashing into homes and tearing roofs from buildings, according to preliminary reports from the National Weather Service.

At least one tornado was confirmed, just after 5:30 p.m. in the village of McGraw, about 30 miles south of Syracuse, N.Y. The Weather Service said that mobile homes in the village of around 1,000 people would likely be “damaged or destroyed.” The extent of the damage was not immediately clear on Monday night.

In Florence, Ala., a 28-year-old man died after he was struck by lightning in a parking lot in the city, about 60 miles west of Huntsville, local police said. And in Anderson, S.C., a 15-year-old boy was killed when a large tree fell and struck him, according to local fire officials.

In Pennsylvania, a person was injured when a tree fell on the car they were in, according to the preliminary reports.

Some of the worst-hit areas were along the Mason-Dixon line and the southern Appalachians, said David Roth, a meteorologist with the National Weather Service.

He cautioned that while the line of storms, known as a bow echo, had moved off the New Jersey coast, there was still a risk of “excessive rainfall” overnight into Tuesday across parts of upstate New York and Vermont. There, he said, “the heavy rainfall may just be beginning,” noting that the region could expect several inches.

In Cambridge, Md., several inches of rain caused flash flooding that stranded a handful of people in their cars on deluged roads, said Rob Kramer, Jr., a Dorchester County councilman. All had were rescued on Monday night, and none were injured, Mr. Kramer said. “The water is receding, but we have several roads that are underwater at the moment,” he added.

As of around 9:30 p.m. on Monday, more than 750,000 homes and businesses across the Eastern United States remained without power, according to poweroutage.us.

Jesus Jiménez and Lauren McCarthy contributed reporting.