Flight disruptions are climbing as severe weather hits multiple busy Northeast airports.

The flight tracking site FlightAware reported more than 600 cancellations and nearly 3,500 delays on Tuesday, including significant impacts to New York-area hubs.

Delays and cancellations impacted four in 10 flights departing the LaGuardia and Newark airports and about a quarter of flights at John F. Kennedy International Airport, FlightAware reported.

The Federal Aviation Administration reported approximately four-hour delays on average for flights to JFK. Flights to Newark and LaGuardia were experiencing delays longer than three hours on average, the FAA said.

Storms were also interrupting flights at the Philadelphia and Boston airports. Those airports and the three major New York airports are under a ground stop, due to the storms.

The FAA said it may also be forced to hold or slow flights in Florida later on Tuesday due to storms.