The snowpack above an elevation of 8,000 feet has very poor structure. The recent snow has loaded a persistent weak layer and created conditions that are ripe for avalanche accidents. In the Teton and Southwest Trails forecast areas large slab avalanches have been remotely triggered by snowmobilers and skiers. Dangerous slabs lurk on slopes that are familiar and enticing to skiers and snowmobilers. Some of these slopes are stable and some are not. In these conditions expert snowpack stability skills are not capable of determining individual slope stability. Excellent route finding skills that avoid slopes of concern and their run out zones are essential for safe travel today. Natural and human triggered slab avalanches have occurred in unusual locations. Poor snow structure with isolated areas of instability may exist below an elevation of 8,000 feet.
Unstable conditions exit on slopes where recent new snow lies upon a persistent weak layer of faceted snow. Slab avalanches up to three feet in depth have been remotely triggered by skiers and snowmobilers. As these slabs slowly gain strength it is more likely that these slabs will fail after people are on them as opposed to while they are approaching them.
( Discussion is generated from the previous day's afternoon forecast. )Skies will be clear above areas of morning fog that will dissipate before noon. Temperatures will be slightly inverted and will drop into the single digits in the morning and rise into the 20s in the afternoon. Winds will back to the west and increase. Skiers and riders are remotely triggering dangerous slab avalanches. These slabs will slowly gain strength. Humans who venture towards them will get further (actually out on them) before they fail. In this manner unstable slopes actually become more dangerous as they become less sensitive to human triggers. These slabs are generally one to two feet deep. These dangerous slabs lurk on slopes that are familiar and enticing to skiers and snowmobilers. Some of these slopes are stable and some are not. In these conditions expert snowpack stability skills may not suffice. The answer is smart terrain choices. Stick to green light terrain.The general avalanche hazard is expected to be CONSIDERABLE at the mid and upper elevations and LOW below an elevation of 7,500 feet.
