Human triggered avalanches continue to be a hazard in steep terrain at all elevations. Yesterday afternoon a party with experience and local knowledge triggered a wind slab avalanche in the Turkey Chute on Peak 25 Short in Grand Teton National Park. One skier was caught, carried and lost a ski but was not injured. This event occurred on a northwest aspect. On Thursday afternoon a skier triggered a wind slab avalanche on a south facing aspect in the southern Teton Range. He was caught, carried and injured. Similar events are likely to be triggered today by skiers or riders who venture into steep wind loaded avalanche starting zones, cliff areas and steep couloirs.
Surface slabs formed by southwest to west winds during the most recent storm cycle could be human triggered on a variety of aspects. These slabs could be one to three feet deep at the mid and upper elevations and up to two feet deep at the lower elevations. These slabs may be more sensitive to human triggers during the warmer portion of the day.
At the upper elevations full depth slab avalanches are unlikely, however they continue to be a concern in large active avalanche paths that face east through north. A release of one of these destructive avalanches may require a large trigger like a snowmachine or a cornice failure.
Dry conditions with a strong temperature inversion will continue. Skies will be mostly clear overhead. Fog will develop in the valleys early in the morning and slowly dissipate during the later morning hours. Temperatures at dawn are expected to be near zero at the higher elevations and near 20 below zero in the valleys. Daytime highs should rise to around 20 degrees at all elevations. Winds are forecast to be northerly ay 5 to 10 miles per hour.Surface slabs formed by strong west to southwest winds are becoming less sensitive to human triggered and less widespread in extent. However areas of wind slab one to three feet in depth could still be triggered by humans in steep wind loaded avalanche starting zones, cliff areas and steep couloirs. Large deep slab avalanches continue to be a hazard in steep north facing terrain above an elevation of 9,000 feet. The likelihood of triggering one of these dangerous slabs is greater in the Togwotee Pass and Greys River areas, especially for larger triggers like snowmachines. Conservative terrain choices are warranted. The general avalanche hazard is expected to be MODERATE in the Teton and Togwotee Pass areas and CONSIDERABLE in the Greys River area.
