MEREDITH, N.H.—The steep bowl at Tuckerman Ravine on New Hampshire’s Mount Washington has long made it a favorite spot for expert skiers and snowboarders who are seeking adventure beyond the comparative safety of the state’s ski areas.

Tuckerman Ravine is seen at left, about one mile below the summit of 6,288-foot Mount Washington, in New Hampshire, on May 4, 2015. Robert F. Bukat/AP Photoy