This avalanche was most likely triggered by a group of skiers from some distance away while ascending a safe ridgeline. This is the largest avalanche that we've seen this season. Northwest winds recently loaded the slope which is north facing and has buried faceted snow acting as a weak layer near the ground. This is a repeat offender for the Alta Snow Safety crew, however, avalanche mitigation on this slope has not started for the season and is, in essence, backcountry terrain.
The party stated that they thought they may have heard a sound but were unaware that they may have triggered anything. PLEASE CONTACT ALTA CENTRAL (801-742-2033) IF YOU REALIZE YOU HAVE TRIGGERED A SIGNIFICANT AVALANCHE NEAR THE SKI RESORTS. This will aid in reducing confusion about the avalanche and any potential rescue personnel.
Photo - Dave Richards
Photos - Mark White