ATC Question, or what was going on on the East Coast Tues?

I was listening to Tuesdays ATC at JFK and PHL from around 5pm that day, and
both airports were basically at a standstill for departures. At PHL planes
were back and forth between tower and clearance getting clearances and
revised clearances. At JFK the tower was relaying clearances to the planes.
Pretty much everyone had their engines shutdown while waiting for "route
approvals". Was this because of storms? There were a couple of times that a
plane would get a revised clearance, but by the time ATC was able to clear a
path to the runway the clearance would be void and they'd shut em back down
waiting for a new clearance. Crazy.

John K.
PP-ASEL