ANGELES NATIONAL FOREST ( — A sinkhole has forced the closure of Angeles Crest (2) Highway in the Angeles National Forest.

A small hole appeared in the road and began to crumble and collapse into the much bigger cavern underneath, U.S. Forest Service officials said Thursday on Facebook.

The highway, popular during the summer months with motorcycle riders and campers headed for the various trails and campgrounds throughout the forest, is closed just west of the Big Pines Visitor Center between Grassy Hollow and Islip Saddle. The sinkhole appeared just west of the Grassy Hollow Visitors Center.

Damage response engineers are estimating 30 days to conduct repairs.