fly.faa.gov doesn't show any arrival delays at IAD. WAS-NYC is mostly red with some orange. Definitely doesn't look good.

Edited to add: There have been lots of flights that have been landing (at least as of 4:40pm) according to flightarrivals.com

Edited again: Flight diversions all over it seems. LH 418 from FRA diverted to EWR as one example.