At least 24 people have died and thousands have been displaced following intense flash flooding in the US states of New York, New Jersey and Pennsylvania

Basement apartments filled with water, subways were forced to close and roads became rivers in what is the aftermath of Hurricane Ida.

New York City Mayor Bill de Blasio described the scenes in his electorate as a “historic weather event”… following the National Weather Service issuing a flash flooding emergency warning for the first time ever.

Recovery efforts are continuing, with authorities working around the clock to restart the transportation systems that are used by millions of people daily.

The National Weather Service says the storm dumped around 7 centimetres of rain per hour between Philadelphia and New York City.

Meanwhile, thousands remain without power in Louisiana, with fears it could take weeks to restore power to residents in the state.