A powerful storm system moved across the northeastern United States, disrupting power and air travel. New York, Boston and Philadelphia were in its path. The National Weather Service warned of possible serious flooding in low-lying coastal areas, on roads and in homes and shops.

At around 17:00 Greek time, more than 75,000 households and businesses in four northeastern states were without electricity, according to poweroutage.com. FlightAware reported hundreds of cancellations, including 130 at Boston’s Logan Airport.

New York’s Global Citizen festival in Central Park was cancelled. Lenny Kravitz, Lauryn Hill and Alicia Keys had been scheduled to perform. Organisers said safety had to come first. Concerts by British pop star Ed Sheeran were also cancelled.

Strong winds affected operations outside UN headquarters during the General Assembly: media organisations were asked to move equipment indoors. Some areas of Massachusetts, including Boston, were forecast to receive a month’s worth of rain.

The figures describe the situation at the reported observation time, while flood levels were forecasts and warnings from meteorologists. The report did not give a region-wide final cancellation total or a power-restoration timetable.