“This has been a very difficult and dangerous storm,” Buffalo’s mayor, Byron Brown, said at a news conference on Monday. “It’s been described as a once-in-a-generation storm. And everything that has been forecast, we have gotten in the city of Buffalo, and then some.”

A driving ban remained in place in Buffalo, a city of around 270,000 people, and in some of its immediate suburbs as the authorities pleaded with residents to remain home.