One hiker was killed and another injured after the cliff at the Arch Rock overlook at Point Reyes National Seashore in Marin County collapsed into the shoreline 70 feet below, officials said Sunday.
A photo released by the National Park Service shows a huge section of the cliff disintegrated into boulders and rocks onto a beach below.
The cliff that collapsed was closed to visitors, said park spokesman John Dell'Osso, after the park received reports Thursday of large fissures that had developed and seriously weakened the cliff. There were signs at the visitor center warning about the closure of the cliff, and four consecutive notices on a trail leading up to the edge that the cliff was now too dangerous to walk on.
"We just put up warning signs this past Thursday and Friday," he said in an interview. "I can't tell you why somebody would walk past those signs and not pay any attention to them."
"This is a tragedy," he said.
The victims were two adults, found atop the pile of boulders and rocks that broke apart during the cliff collapse. The surviving hiker suffered non-life threatening injuries and was being treated at Santa Rosa Memorial Hospital.
The cliff that collapsed was the end of the most popular trail at Point Reyes National Seashore, a 4.2-mile route called the Bear Valley Trail that is the shortest route between the Bear Valley Visitor Center and the Pacific Ocean.
The collapse of the cliff partially buried the Arch Rock below it, the spokesman said. Arch Rock is a rock formation that has been carved in an arch shape due to erosion by ocean waves.
The cliff was made out of a sandy formation that's unstable, the spokesman said. On its website, the park service says that California coastal bluffs are inherently unstable and prone to crumbling.
The park service's general advice: Not only is it very dangerous to climb or walk on the edge of any cliff, it's also unwise to be at the base of any rock face in case rocks tumble down.
"You would never want to walk too close to the edge. If it were to break off, you would fall," Dell'Osso said.
The collapse of the cliff occurred some time before 6 p.m. Saturday.
The Point Reyes National Seashore is only about an hour's drive from much of the San Francisco Bay Area, and has 150 miles of trails and 80 miles of coastline. It receives about 2.5 million visitors a year. The area is well-known to geologists because it sits in the San Andreas fault zone. The San Andreas caused the great San Francisco earthquake of 1906.