Henri is a rare tropical storm to strike America's north-eastern seaboard and comes as the surface layer of oceans warms due to climate change
Tropical Storm Henri was downgraded to a tropical depression on late Sunday after slamming into Rhode Island on the US east coast, knocking out power to thousands of Americans, uprooting trees, and bringing record rainfall.
The storm hit land near the town of Westerly, Rhode Island, at approximately 1615 GMT, the National Weather Service said. Henri had already been downgraded from a Category 1 Hurricane earlier on Sunday.
But the National Hurricane Center (NHC) said in its 0900 GMT advisory that Henri was "nearly stationary" and winds had reduced to 48 kilometers per hour -- much lower than predicted gusts of 75 mph -- with "little change in strength" forecast.
Henri is a rare tropical storm to strike America's north-eastern seaboard and comes as the surface layer of oceans warms due to climate change.
The warming is causing cyclones to become more powerful and carry more water, posing an increasing threat to the world's coastal communities, scientists say.
Millions of residents in New England and New York's Long Island had been told to prepare for violent winds, days without electricity, and storm surges of up to five feet.
Rhode Island Governor Dan McKee said there was "significant flooding" in areas. There were no immediate reports of any casualties.
By mid-afternoon, the NHC had lifted all surge warnings and initial reports from residents indicated the storm was not as bad as projections feared although fallen trees nearly damaged homes in Groton, Connecticut.
Residents on Long Island, home to the plush Hamptons villages where wealthy New Yorkers retreat in summer, expressed relief that the storm's path had skirted east of them.
In Newark, New Jersey, flash flooding caused havoc with emergency services rescuing 86 people, including 16 children, from submerged vehicles.
In Helmetta, 30 miles south, volunteer firefighters waded through waist-deep water to help evacuate residents from waterlines rising dangerously close to their homes.
Some 79,000 people lost power in Rhode Island and another 33,000 suffered blackouts in Connecticut, according to the tracking website poweroutage.us.
More than 200 flights were cancelled at Newark airport while New York's LaGuardia and JFK airports cancelled almost 200 between them, they said.
President Joe Biden ordered the Federal Emergency Management Agency (Fema), to coordinate disaster relief efforts in Rhode Island, Connecticut, and New York, where Governor Andrew Cuomo deployed 500 National Guard soldiers.
Henri missed New York City by several miles but still caused tropical storm conditions overnight and throughout Sunday, where a flash flood warning was in effect until 5:45pm, local time.