Deadly Tropical Storm Isaias knocked out power to millions on the US east coast after making landfall in North Carolina as a hurricane.
Two people died when a tornado struck a mobile home park. At least two others in New York and Maryland also died.
The National Hurricane Center (NHC) had warned of “the danger of life-threatening storm surge”.
The storm, with 65mph (100km/h) winds, moved into New York state on Tuesday afternoon.
It is the ninth named storm of the year.
From North Carolina up to New York, Isaias left over 2.8 million residents without power. It has spawned tornadoes, uprooted trees, damaged homes and caused floods and fires.
Isaias was downgraded to a tropical storm after hitting islands in the Caribbean last week, but was re-categorised as a category-one hurricane as it approached the Carolinas on Monday.
It was then downgraded again to a tropical storm, but storm surge warnings remain in effect along the coast.
As of Tuesday afternoon, Isaias was moving north at 40mph (65km/h), the NHC said.
Strong winds, with gusts reaching hurricane force, are expected all along the Mid-Atlantic coast and as far as New England on Tuesday.
As of Tuesday afternoon, local time, the storm was sprinting across eastern New York towards southern New England with strong and damaging winds.