MANTEO, N.C. (AP) — Debris from two houses that collapsed into the surf on North Carolina's Outer Banks are washing onshore, prompting the National Park Service to issue warnings to visitors walking along the Cape Hatteras National Seashore.

The park service said in a news release on Wednesday that some of the debris is covered by sand and some of it is fully exposed. Officials advise visitors to wear hard-soled footwear on the beach between Rodanthe and Salvo, although sharp debris may also be found in areas south of Salvo.

The unoccupied homes were located along Ocean Drive in the Outer Banks community of Rodanthe.

A third house in Rodanthe collapsed in February.

While larger pieces of debris have been removed, miles of small pieces of debris remains on and under the surface of the beach, the park service said. Seashore workers are aware of wood with exposed nails, splintered wooden fragments and other debris that could be harmful to beachgoers without hard-soled footwear.

In addition to the debris, erosion at the Buxton Beach Access has exposed PVC pipes and other items associated with decommissioned military facilities in the area. Workers are cutting the pipes and removing as much of the exposed debris as possible.