Authorities said the cause of the fall is believed to be anchor failure while the climbers rappelled a steep gulley.

Three rock climbers fell to their deaths Sunday in Washington state, authorities said. Investigators believe their equipment failed as they were descending a ravine.

Many details about what led up to the fall still aren’t known, said Cristina Woodworth, who leads the sheriff’s search and rescue team. But all four climbers appeared to be tied to the same piton when it failed.