Update, 8:35 p.m.: U.S. Park Police confirm that all northbound lanes of the GW Parkway near Spout Run Parkway have reopened.
Earlier: Northbound George Washington Parkway past Spout Run Parkway will be closed until at least 10 p.m. because of debris on the road.
Rocks have tumbled onto the roadway, authorities say. All northbound lanes are blocked.
Traffic is being diverted onto Spout Run Parkway to I-66 Westbound. Delays begin near the Roosevelt Bridge, approximately 1.5 miles. Drivers should avoid this area and take alternate routes.