Flash flooding killed at least three people in Pennsylvania Saturday evening, and storms moving through the Northeast Sunday threaten heavy rain and tornadoes.
Intense rainfall flooded roadways in Bucks County, Pennsylvania, catching many on the roads by surprise and leaving some trapped, the Upper Makefield Township Police Department said in a statement.
Three people were found dead and four people are still unaccounted for, as search and rescue efforts continued Sunday, police said.
"We are treating this as a rescue but we are fairly certain we are in a recovery mode at this time," Upper Makefield Fire Company Chief Tim Brewer said Sunday.
Several area agencies were assisting with rescue missions overnight.
"Our department is assisting Upper Makefield Township Police Department with a search and rescue operation on Taylorsville Road in the area of Washington Crossing Road (Route 532) for missing persons lost in the flood," said Newtown Township Police Department.
Tornado and Flood Threats
A slow-progressing line of storms moving through the Northeast Sunday has 55 million people under flood threats and 14 million under a tornado watch.
The National Weather Service issued a tornado watch for large portions of the Northeast, including parts of the New York City metro Sunday.
Much of the recently flooded New England region could face torrential rainfall. The weather service issued a Level 3 of 4 threat for excessive rainfall for areas including New York City, Boston, Philadelphia, and Washington DC.
"Given some parts of the Northeast contain saturated and sensitive soils from recent heavy rainfall over the past 10 days, this is a setup primed to produce flash flooding that could be significant in affected areas," the weather service said.
Over the last month, parts of interior New England and the Northeast have seen 200% to 300% of their average monthly rainfall, leading to last week's disastrous flooding event in parts of Vermont, New York and western Massachusetts.
A 35-year-old woman died last week when she was swept away by floodwaters as she tried to evacuate her Orange County home in New York. Officials say the flooding there caused tens of millions of dollars in damage.
Vermont faced flooding of the likes not seen since Hurricane Irene devastated the state in 2011. The intense rainfall gushed through streets and homes, prompting hundreds of evacuations and more than 200 rescues.
President Joe Biden approved an emergency declaration for Vermont, authorizing FEMA to move in needed equipment and resources.
Even with the help, "this is going to be a years -- if not a decade -- long recovery for the state of Vermont," said Jennifer Morrison, the state's public safety commissioner.
Steady warming and atmospheric changes are "supercharging" regular weather events, making them longer and more intense, Michael E. Mann, a climate scientist and distinguished professor at the University of Pennsylvania, told CNN.
Climate experts say it is part of a "perfect storm" this summer, leading to deadly flooding in places like the Northeast while other parts of the world -- including the Southwestern US -- are scorched by record-breaking heat.