PORTLAND, — Damaging winds flattened trees and utility wires and knocked out power in parts of northern New England on Sunday, flights were delayed in New York City and there were reports of a tornado in South Carolina as the East Coast weathered the remnants of violent storms that claimed 13 lives in Oklahoma.

Heavy rain, thunderstorms, high winds and hail moved through sections of the Northeast on Sunday afternoon, knocking out power to more than 40,000 in Vermont, New Hampshire and Maine. The National Weather Service issued a rare tornado warning as a line of thunderstorms raced through New Hampshire into western Maine. The National Weather Service said a tornado warning was issued as radar indicated a possible tornado moving from Kingfield, Maine, to Bingham, Maine. The tornado was not immediately confirmed.

In northwestern South Carolina, authorities checked unconfirmed reports of a tornado, said Jessica Ashley, a shift supervisor for Anderson County’s 911 center. The fire department responded to a report of roof damage to a home and callers said trees were blown over. No injuries were reported.

The weather service said thunderstorms and winds in excess of 60 mph in Vermont produced 1-inch-diameter hail and knocked down numerous trees and wires. In northern Maine, radar picked up a line of thunderstorms capable of producing quarter-sized hail and winds stronger than 70 mph. Forecasters warned of tornadoes.

The prediction for stormy weather in the New York City region produced delays at major airports. La Guardia Airport and Newark Liberty Airport in New Jersey had delays of up to 90 minutes, while John F. Kennedy International had delays of about 30 minutes. Outside Washington, delays were up to nearly two hours at Dulles Airport.

In the southern part of the United States, thunderstorms, high winds and hail were expected as part of a slow-moving cold front. Heavy rains could spawn flash flooding in some areas, the weather service said.

Oklahoma Gov. Mary Fallin toured damage in El Reno, about 30 miles from Oklahoma City. She said the death toll could rise as emergency workers continue searching flooded areas for missing residents.

The state Medical Examiner’s Office spokeswoman Amy Elliott said the death toll had risen to 13 from Friday’s EF3 tornado, which charged down a clogged Interstate 40 in the western suburbs. Among the dead were two children — an infant sucked out of the car with its mother and a 4-year-old boy who along with his family had sought shelter in a drainage ditch.