New York City was hit by rainfall worth 50,000 Olympic-size pools over 5 hours

The remnants of Hurricane Ida have caused dangerous flash floods and tornadoes across the northeastern United States, including across New York, New Jersey and Connecticut.

States of emergency have been declared in New York and New Jersey due to the storms. These are the rarest of weather alerts, and only reserved for when you have life-threatening flooding and water rescues, and catastrophic flooding taking place.

It has never been issued for New York City before, according to CNN meteorologist Pedram Javaheri.

Here’s what you should know:

At least eight people have been killed in storm-related deaths. The New York City Police Department (NYPD) reported seven fatalities in the city and the Mayor Hector Lora reported at least one death due to flooding in Passaic, New Jersey.

There has been an unprecedented amount of rainfall by any metric, Javaheri said. The storm prediction center had warned of a level 4 rainfall — the highest risk for excessive rainfall.

Portions of Rhode Island, Connecticut and Massachusetts will soon see the last bit of thunderstorm activity, as Ida pushes away from the US over the next several hours, Javaheri added.

More than 300 flights were canceled out of Newark International Liberty airport as Newark sees its wettest day in recorded history, Javaheri reported.