Three women killed when a sea cliff collapsed in southern California were members of a family who had gathered to celebrate one of them having survived breast cancer, authorities and relatives said on Saturday.

Anne Clave, 35, and her mother, Julie Davis, 65, died after tons of sandstone were unleashed on Friday at Grandview beach north of San Diego, the county medical examiner said. A family email obtained by KNSD-TV identified the third victim as Elizabeth Cox, Clave’s aunt.

The victims were part of a family gathering celebrating Cox surviving breast cancer, the email said.

Cox died instantly, the email said. Her age was not given.

Clave “enriched the lives of all those around her with the joy and fun she brought to all”, the email said, and Davis was an “incredible grandmother”.

The three women leave behind spouses, children, and many members of their extended families, the news station reported.

“The nature of the accident and the loss is incomprehensible to all of us, our children and those around us,” the email said.

Officials on Saturday reopened much of the popular surf beach that was closed after the tragedy.

Encinitas lifeguard captain Larry Giles said a lifeguard was posted near the collapse zone, which is still marked by yellow caution tape. Someone left a bouquet of flowers on a nearby rock.

A 30-foot-long slab of the cliff plunged on to the sand on Friday afternoon. Geologists were on the scene on Saturday assessing the area around the collapse zone. Homes on top of the cliff were in no immediate danger, Giles said.

A lifeguard reported feeling and hearing the thud as the dense dirt landed on the beach.

Lifeguards and beachgoers scrambled to the towering pile of debris estimated to weigh tens of thousands of pounds to help search for victims.

“I saw first responders, and I saw lifeguards frantically digging people out of the debris,” Jim Pepperdine, who lives nearby, told the San Diego Union-Tribune.

Pepperdine said he saw people trying to resuscitate a woman before her body was covered.

The woman died at the scene, and two more people later died at hospitals. Another person was taken to a hospital, and a person who had minor injuries was treated at the scene, officials said.

Authorities said they were all adults.

Search dogs were brought in to hunt for other possible victims, and a skip loader was used to move the dense, heavy debris. No other victims were found.

Suburbs north of San Diego have long contended with rising water levels in the Pacific Ocean that pressure bluffs along the coast. Some are fortified with concrete walls to prevent multimillion-dollar homes from falling into the sea.

Long stretches of beach in Encinitas are narrow strips of sand between stiff waves and towering rock walls. Grandview beach can be reached by wooden stairs from a parking lot above.