Authorities warn residents that extreme conditions could pose risks and urge people to stay away from flooded areas.

Residents of the northeastern United States are facing a powerful storm known as a nor’easter that has knocked out power and caused flooding across the region.

The storm has led to the cancellation of more than 400 flights and power outages affecting more than 88,000 homes and businesses as of Saturday afternoon local time. That figure is down from a high of 119,000 earlier in the day.

Bob Oravec, lead forecaster with the National Weather Service in College Park, Maryland, said that the storm is likely to persist, with “a lot of high winds, a lot of high tides and heavy rain possibility over the next few days for the northeastern US”.

The governors of New York and New Jersey declared states of emergency in counties expected to see the worst of the storm, including New York City, on Friday.

Authorities have also warned residents about the risks of flooding and high tides, cautioning people to stay away from the beach and areas inundated with water.

“Anyone who goes in or near the water this weekend is literally gambling with their life,” New York Governor Kathy Hochul said.

Despite the warnings, people have been seen kayaking down flooded streets in Long Island, New York, while others took advantage of large swells in Hampton, New Hampshire.

“In all the canals, the water is up really high and coming into people’s back yards,” Jay Boyd, a resident of Ocean City, Maryland, told The Associated Press news agency.

Oravec said that nor’easters are not unusual as the region of New England enters the autumn season, but that “this might be a little earlier than average for a big storm”.

About 425 flights have been cancelled and 1,338 delayed so far on Saturday, according to data from the flight tracker FlightAware.

Concerts and sporting events have also been cancelled, including musician Ed Sheeran’s scheduled shows in the state of Massachusetts on Friday and Saturday.