Two tornadoes have swept out of the sea and hit parts of New York City, hurling debris in the air, knocking out power and disrupting the US Open tennis tournament.
Videos show a funnel cloud sucking up water, then sand and small pieces of buildings as it moved through the beachside Breezy Point area in the borough of Queens.
The National Weather Service had issued a tornado warning for the boroughs of Queens and Brooklyn about 10.40am on Saturday (0040 Sunday AEST), but the first storm still took people by surprise when it struck Queens half an hour later.
About 10 minutes after, a second, stronger tornado touched down in Brooklyn. No injuries were reported in either incident.
Tornadoes were once extremely rare in New York, but have occurred more frequently in recent years.
Play was affected at the US Open tennis tournament, being held in Queens a few kilometres from where the first tornado struck.
Tennis fans watching on television caught a glimpse of New York's extreme weather. A wind-tossed men's semifinal between Novak Djokovic and David Ferrer was halted in its first set. It is slated to resume about 11am on Sunday (0100 Monday AEST).
The women's final between Serena Williams and Victoria Azarenka, scheduled for Saturday night, had already been postponed until Sunday because of forecast rain.
"I was showing videos of tornadoes to my four-year-old on my phone, and two minutes later, it hit," said Breezy Point resident Peter Maloney. "Just like they always say, it sounded like a train."
In the storm's wake, the community of seaside bungalows was littered with broken flower pots, knocked-down fences and smashed windows.
The tornadoes struck as part of a line of storms expected to bring damaging winds, hail, heavy rain and possibly more tornadoes throughout the mid-Atlantic and northeast region on Saturday.
The storm system killed four people, including a child, in Oklahoma on Friday.
