Stevens Pass, WA – A Seattle area snowboarder who ventured out of bounds while riding at Stevens Pass in Washington died Sunday in an avalanche.nRiley McCarthy, 20, a sophomore at the University of Washington, was snowboarding with three friends out of bounds around 4:30 Sunday afternoon in an area known as Cowboy Mountain when the avalanche released, forcing him into a tree.

McCarthy’s companions summoned the Stevens Pass Ski Patrol via cell phone following the incident. They administered CPR to McCarthy, who was not breathing, until help arrived.

King County medical examiner’s office says that McCarthy died of asphyxiation.