UPDATE: Northbound Interstate 81 is once again open, but some residual backups may take some time to entirely clear.

PREVIOUS:What VDOT calls a “security-police activity” is blocking a portion of northbound Interstate 81 through the Salem area — and creating some major backups. It means all northbound traffic is being taken off the highway at Thompson Memorial Drive, exit 140. So far, there is no word on what exactly the police activity is, but VDOT traffic cams show police dogs at the scene.

From VDOT at 10:55 am: On I-81 at mile marker 140 in the County of Roanoke, motorists can expect delays due to other security/police activity. All north lanes are closed. The north entrance ramp is closed. Traffic backups are approximately 5.5 miles. Traffic is being detoured off at Exit 140. The on ramp at Exit 141 is also blocked. Expect delays.