DANA POINT — Orange County parks officials say they will monitor a cliff area under Cannons Restaurant after about 18 tons of rocks, including a two-ton boulder, dropped Jan. 13, smashing into a public restroom below.

The restroom is across from Baby Beach at the north end of Dana Point Harbor. Since the rock slide, OC Parks, which manages the harbor and surrounding area, has closed Cove Road and the nearby gazebo at the Sampson Overlook. The area near the bathroom also has been sealed off.

“OC Parks’ engineering contractor will be conducting further assessments of the bluff in that area,” said Marisa O’Neil, spokeswoman for OC Parks.

“The county does survey the area just north of the fall, where the crib wall (a retaining wall) is located below the restaurants, but not the area of the fall, which is a separate, adjacent formation,” she added. “This is monitoring for land slippage in that area that has had previous falls.”

The incident was first reported to the Orange County Sheriff’s Department at 3 p.m. Jan. 13. Locals who reported the slide on Facebook said a large boulder landed on the lawn near a picnic table close to where the road climbs along to the top of the bluff.

Though there were people walking their dogs close by, no injuries were reported, said Sgt. Rich Himmel.

Gayle Beckenhauer, of Dana Point, was passing the area headed toward the Ocean Institute shortly after the boulder and other rock came crashing down.

“Anyone could have been standing there,” she said. “It was busy in the harbor when it occurred. It was scary to see how large it was. I wonder if other sections of the cliff are loose.”

The incident is the second time rocks have fallen from that area.

John Foster, a geological engineer at Cal State Fullerton, said the area — known as the “quiet Cannon slide” — is a repaired landslide. That means the slope was engineered back under the restaurant.

“When that (first) landslide happened, you could walk into the restaurant balcony and feel it move up and down,” he said.

But the latest rock fall was in a different rock formation.

“A rock fall like that would have fallen straight down and then rolled,” he said. “It could have seriously injured someone. Lucky no one was hurt.”

The rocks, which fell about 50 feet, were part of a four- to five-million-year-old rock formation called the Capistrano Formation, Foster said.

For now, OC Parks has the area fenced off.

“Once we receive the report from our engineers, we will determine next steps based on their recommendations and safety considerations,” O’Neil said. “The bathroom is a total loss and the picnic shelter was not damaged.”

O’Neill said it was unclear whether the restroom would be rebuilt.

According to Foster, possible fixes could include a chain link fence to catch boulders and rocks from rolling out. He said there is an area in Laguna Canyon near the Festival of Arts grounds where chain link fence has been draped over a weak rock slope.

“That is not very attractive,” he said.