County officials, police departments and other agencies were fielding dozens of emergency calls prompted by the flooding.
A slow-moving storm system brought heavy rain across a wide section of New York State on Sunday evening, flooding streets, prompting rescues for drivers whose vehicles were stranded on inundated roads and causing at least one death, the authorities said.
Two areas received more than three inches of rain as of Sunday evening and appeared to be the most affected, according to the National Weather Service: Rensselaer County and nearby towns, and farther south in the Hudson Valley, including Dutchess, Orange and Ulster Counties.
Steven M. Neuhaus, the Orange County executive, said that there had been one death related to the flooding. State Senator James Skoufis, who represents Orange County, said that the victim was a woman in her 30s, though neither official had details on the cause of death or circumstances.
Mr. Neuhaus said that there had been multiple calls for water rescues in the vicinity of West Point and Highland Falls, both of which are on the western shores of the Hudson River. Mr. Skoufis, who was in Orange County on Sunday evening, said that Gov. Kathy Hochul intended to declare a state of emergency in the county, noting that in Woodbury the two major arteries in and out of town were washed out.
“If you’re traveling within Orange County, good luck,” the senator said. “Getting around is next to impossible right now.”
County officials, police departments and other agencies were fielding dozens of emergency calls prompted by flooding that the Weather Service described as “life-threatening.”
Flash flood emergencies — which indicates not only that flooding is occurring, but that it is posing a severe threat to human life — were issued for stretches of the state.
Additional rainfall and flooding were expected in the Hudson Valley overnight, prompting some towns to declare states of emergency. Flash flooding was also possible in New York City, Spring Valley and Monsey through Sunday evening, the Weather Service said.
In Saratoga County, near the town of Waterford, Routes 4 and 32 were flooded with up to two feet of water, Andrei Evbuoma, a meteorologist with the Weather Service in Albany, said.
Portions of nearby roads in the area were impassible, he added, complicating rescue efforts.
Alan C. Mack, the deputy commissioner of emergency management in Orange County, said on Sunday evening that officials were still trying to get a full assessment of the possible damage and danger.
“We’ve got to the point where we know there are people in trouble, and we can’t get to them because the roads are all blocked,” Mr. Mack said, adding that he did not know how many people were stuck.
In Cornwall, a town in Orange County, the local office of emergency management urged residents on Sunday night to “get to higher ground” if their location was not safe. “Travel is impossible,” the office said on Twitter.
Mudslides, stranded vehicles and flooded roadways were reported in town, according to the office.
A New York City-bound Amtrak train was halted, as it approached Poughkeepsie on Sunday evening, with an Amtrak employee saying over a loudspeaker that there had been a “complete washout of both tracks” south of the city, preventing any travel by train.
The train was put in reverse so it could travel back to Rhinecliff, N.Y., where Amtrak officials were determining what to do with the passengers onboard.
Oliver Mackson, who lives in Poughkeepsie, said he was heading home from Yankee Stadium by train when an announcement informed passengers that the ballast had been washed out of the tracks north of the Croton-Harmon station, about 35 miles south of Poughkeepsie.
“Everybody is being pretty subdued,” Mr. Mackson said of the passengers on the train. “It’s very jarring,” he added. “It’s just your basic suburban family bonding experience, and all of a sudden it’s turned topsy-turvy.”
Gov. Hochul had been warning residents for several days about the potential for flash flooding.
Ms. Hochul also noted that “the ground is so wet already” after previous storms, making it difficult for the soil to absorb more water. She added that the State Police, rescue teams and utility workers had been deployed in advance of the heaviest of the rains.
The Orange County executive, Mr. Neuhaus, said he was requesting additional help from the State Police and the governor. “We’re doing our best here,” he said.
Flooding is a complex phenomenon with many causes, including land development and ground conditions. Although linking climate change to a single flood event requires extensive scientific analysis, climate change — which is already causing heavier rainfall in many storms — is an increasingly important part of the mix.
Warmer atmosphere holds and releases more water, whether in the form of rain or heavy winter snowpack.
Mr. Skoufis and other officials were also girding for additional rain overnight, saying that if the prediction holds, “it’s probably going to get worse.”
Nicholas Bogel-Burroughs contributed reporting.