An avalanche on Mount Everest, the tallest peak on earth, swept through an area just below Camp 2 early Friday morning, killing six local guides. Nine more are missing following the avalanche, which hit around 6:30 a.m. local time.

Climbing season for summiting Everest’s peak does not start before May 15, nearly a month from now. Those hit by the avalanche were climbers and guides setting ropes and preparing camps. Camp 2 is at 21,300 feet above sea level, 8,000 feet below the summit.

Four bodies have been recovered and two more are being dug out. The other nine unaccounted for are also Sherpa guides.

In 2013, there were eight confirmed deaths on Mt. Everest.

UPDATE 6:16 a.m.: Bodies of six of the missing guides have been recovered by search crews, raising the death toll from the avalanche to 12. Three people remain missing.