Undercut roads are just one hazardous condition Tropical Storm Helene created along the Blue Ridge Parkway/NPS

Tens of thousands of downed trees littering roadways and forests. Landslides. Mud slides. Undercut roads.

Those are the conditions National Park Service crews have found as they worked their way along the Blue Ridge Parkway in North Carolina and Virginia.

"The slides have occurred above and below the road and have also severely damaged or swept away the roadbed in numerous places," a Park Service release said Tuesday evening. "Damage in Virginia is less severe, but work still remains to clear roads of trees and brush to make the parkway safe for use."

As the crews continue to assess things along the 469-mile scenic highway that links Shenandoah and Great Smoky Mountains national parks, there is no firm date when the parkway will reopen to traffic. The closure applies to hikers, as well.

A landslide at milepost 348 covers the parkway/NPS

"The National Park Service reminds the public that the full closure of the Blue Ridge Parkway and associated park trails applies to all vehicles and uses — motor vehicles, bicycles and pedestrians. Hazards both seen and unseen endanger unauthorized users and some threats may not be obvious, such as weakened road structures or hanging limbs, which are subject to falling in changing weather conditions," the release noted. "The parkway is also an active work area, with vehicles and heavy equipment moving through the area."

Tracy Swartout, the parkway's superintendent, said "[T]he damage left behind by the storm has created dangerous conditions, some of which are not immediately visible from the road itself. We thank the public for their cooperation in respecting closures for their safety and to allow crews to complete their work.”

Due to the significantly lighter storm impacts in Virginia, the Park Service is finishing up damage assessments and the clearing of debris there and is targeting a phased reopening of most of the parkway in Virginia within the next week.

Landslide at milepost 307 along the Blue Ridge Parkway/NPS