( CNN ) One person died and another was severely injured after a cliff collapsed on the Pacific Coast north of San Francisco , the National Park Service said . The two people fell about 70 feet ( 21 meters ) Saturday when part of the Arch Rock overlook at Point Reyes National Seashore gave way . The day before the collapse , the Point Reyes National Seashore had posted a photo on Facebook of a fissure in the rock structure -- with a warning to use caution . `` Visitors using Bear Valley Trail to Arch Rock -- watch out ! At the very end of the trail , the cliff is breaking away -- seen here in a photo taken Wednesday , '' the government organization said . The NPS said hazardous conditions had been reported to it on March 19 . John Dell'Osso from the Point Reyes National Seashore told CNN that it had posted warnings after being notified last Thursday that a crack had formed in the arch . `` We posted all kinds of notices up and down that particular trail , which is how probably how 99 % of the people who would hike that far would ( go ) , and all around our visitors ' center in Trail Heads , just to warn people of the hazard that was out there , '' Dell'Osso said . `` We did n't know what could happen and what unfortunately did happen is on Saturday afternoon a large portion of that overlook actually collapsed down onto the beach and partly onto the ocean , '' he said . `` The tragedy is that there were two people that were standing out there who fell with all of that rubble . '' On Monday , the Marin County Sheriff 's Office named the deceased as 58-year-old Nancy Blum , from California . It said she had been hiking about 6:30 p.m. Saturday `` when a structural collapse of the rock occurred . '' After emergency personnel reached Blum and her hiking companion , she was flown to Bear Valley Ranger Station , where she was pronounced dead . The National Park Service and the county coroner 's office are investigating the cause of Blum 's death . `` The cause of death will be pending the completion of toxicology studies , '' the sheriff 's office said in a statement . Bluffs along the California coast are known for being unstable , according to the park service . The Arch Rock trail that runs along that part of the coast has been closed until further notice . CNN 's Joe Sutton contributed to this report .
Officials had posted warning Friday that cliff was dangerous . Two people fell about 70 feet when California at Point Reyes National Seashore collapsed .