Slow-moving storms that have left at least one dead in Orange County, New York, are dumping heavy rainfall at intense rates over parts of the Northeast, forcing road closures, water rescues and urgent warnings about life-threatening flash floods.
Already, floods have inundated roadways in parts of New York, and Gov. Kathy Hochul has deployed state police and swift water rescue teams as the state braces for more road floods and washouts.
A woman died after being swept away in floodwaters in New York's Orange County, which is among the areas hit hardest by floods, authorities told CNN. Hochul has declared an emergency for the county.
"We are approaching a critical point in this weather event, and New Yorkers must remain vigilant," Hochul said Sunday night. "Remember: avoid flooded roads, monitor your local forecasts and have an evacuation plan ready if you're in a danger zone."
Rainfall in West Point, New York, totaled more than 7.5 inches in six hours Sunday afternoon, according to preliminary data from the National Oceanic and Atmospheric Administration. That's a 1-in-1000 year rainfall event for the area, according to a CNN analysis of NOAA's historical rainfall frequency data.
A once-in-a-millennium rainfall event is one that is so intense, the chances of it happening in any given year is just 0.1%.
Flash flood warnings and watches are in place through Monday in parts of New York, Vermont, Massachusetts and Maine -- as well as across the country in Washington and Alaska.
A moderate risk, level 3 of 4, of excessive rainfall is in place from New England to the Mid-Atlantic through early Monday morning.
Intense rainfall rates are expected to continue in Vermont and northeastern New York on Monday, according to the National Weather Service. New York could see 1 to 2 inches of rain per hour, the NWS warned.
In Vermont, Gov. Phil Scott declared a state of emergency as the weather service warned flash flooding could become "extremely dangerous." "Significant to potentially catastrophic flash flooding is likely, especially in areas that have recently received heavy rainfall," Vermont transportation officials tweeted.
"The threat is exacerbated by the fact that the ground is already saturated from recent rainfall events," the National Weather Service said.
Several additional inches of rain falling over the area in a short period of time -- over mostly saturated ground -- could set the stage for significant flash and river flooding, as well as mud slides, the National Weather Service warned.
"Flash flood warnings mean travel is extremely dangerous. Please, don't take any chances," Hochul said. "Stay home, stay off the roads, and stay safe."
For millions of New York City residents, a flood watch is in effect until 6 a.m. Monday morning, the city said on its website, adding that areas that were low-lying, had poor drainage or are close to creeks, streams or rivers are particularly at risk for flash flooding.
New York City's Emergency Management Department cautioned residents living in basement apartments "to be prepared to move to higher ground." Heavy rains continuing through Monday morning "may cause rapid flooding to basements with little to no notice and can be life threatening," an alert from the agency sent Sunday afternoon reads.
"Do not underestimate the power of fast-moving water," Hochul said. "Two feet of fast-moving flood water will float your car, and water moving at two miles per hour can sweep cars off a road or bridge."
Trapped drivers had to swim out of their cars
In New York's Orange County, people got trapped by floodwaters at the US Military Academy at West Point and had to swim out of their cars to get to safety, a West Point Military Police spokesperson told CNN Sunday.
The town of Cornwall, also in Orange County, issued a "No travel Advisory" Sunday after storms flooded multiple roads, triggered mudslides and forced rescues from stranded cars.
"TRAVEL IS IMPOSSIBLE," Cornwall emergency officials said on Twitter. "GET TO HIGHER GROUND. IF SAFE, STAY WHERE YOU ARE."
In nearby Rockland County, New York State Police reported "numerous motorists stranded" due to flooding in the area.
State Police, local fire departments and EMS are using personnel and equipment to assist motorists and "get them to safety as fast as possible," spokesman Steven V. Nevel told CNN in an email Sunday.
Firefighters in Canandaigua in Ontario County, New York, received over 150 water related calls and performed dozens of rescues, Canandaigua Fire officials tweeted Sunday, sharing a photo of people kayaking through water deluged streets.
Across state lines, eastern Pennsylvania also saw "significant" flash flooding Sunday afternoon, according to the National Weather Service. The Fleetwood Police Department shared images of deluged roadways in Berks County and urged residents to avoid all travel, adding that crews were out responding to rescues and flooded basements Sunday.