Flash floods kill at least 5 people in Pennsylvania

Authorities in Pennsylvania continue to search for two missing children after heavy rainfall Saturday evening led to destructive flash floods that killed at least five people, including the children's mother.

It was part of a band of strong to severe thunderstorms that swept across the Northeast, affecting millions of people from Maryland to Maine.

Authorities in Upper Makefield Township, located along the Delaware River about 30 miles north of Philadelphia, said Sunday morning that three people died after being "swept away" by floodwaters. They later said two other bodies had been found, bringing the total to five fatalities.

"This is a mass casualty incident the likes of which we have not seen before," the township said in a Facebook post.

Two children — a 2-year-old girl and her 9-month-old brother — are still missing. Authorities identified them Monday as Matilda "Mattie" Sheils and Conrad Sheils.

Their mother, 32-year-old Katie Seley, drowned as she tried to save the two young children.

Jim Sheils, their father, was able to get their 4-year-old son to safety. The children's grandmother also survived and was treated at a local hospital.

The family was visiting the area from Charleston, S.C., and was on their way to a barbecue when they got caught in a flash flood, officials said.

The Bucks County Coroner's Office identified the other four victims of the flash floods as 78-year-old Enzo Depiero, 53-year-old Susan Barnhart, 64-year-old Yuko Love and 74-year-old Linda Depiero.

According to the National Weather Service, more than 40 million people across the Northeast were at moderate risk of excessive rainfall on Sunday, as major storms were inundating the Philadelphia, New York City, Hartford and Boston metro areas and beyond.

NPR's Juliana Kim contributed to this report.