UPDATE (6:14 a.m.) - All northbound lanes of Interstate 81 are open again.
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ROCKBRIDGE COUNTY (WSLS 10) - All northbound lanes of Interstate 81 are closed after a tractor-trailer crash in Rockbridge County, according to the Virginia Department of Transportation.
The crash happened at mile marker 204.
As of 4:40 a.m., VDOT is reporting traffic backups of 2 miles.