INYO COUNTY, Calif. (AP) — Altitude sickness and severe storm conditions likely caused a man to fall to his death while trying to climb Mount Whitney in the eastern Sierra Nevada, authorities said Tuesday.

The Inyo County Sheriff’s Office said in a statement that Eric Goepfert, 50, had planned a five-day, four-night trip in the backcountry. His wife called the sheriff’s office when he didn’t come home as planned Dec. 17.

Two days later, searchers using an avalanche probe found Goepfert’s body under deep snow at the base of the Ebersbacher Ledges.

Investigators said they believe Goepfert was experiencing headache and nausea, which are symptoms of acute mountain sickness. Two major storms also ripped through the eastern part of the Sierra mountain range and the snow, high winds, and single-digit temperatures likely caused him to fall 30 feet (9 meters), they said.

Goepfert served in the U.S. Army and was an active Army reservist.