Dangerous avalanche conditions exist in the backcountry. New snowfall and strong southwest to west winds since early Tuesday morning have formed sensitive wind slabs at all elevations. These slabs will be larger and more sensitive above 8500 feet where the possibility also exists for the release of larger slabs that involving older weak snow layers. Predicting the release of these larger persistent slabs is difficult and requires an evaluation of the snowpack to the ground . The best way to avoid an accident today is by simply making conservative route and terrain choices. At the low elevations, smaller avalanches could be triggered on very steep terrain features and terrain traps should be avoided.
Rapid loading has increased the likelihood for the release of large to very large avalanches involving weak snow buried on December 5th. Such an event could be triggered when a single person hits a weak spot on or near a slope, or by the release of a wind slab. If triggered these slabs could be soft or hard, have depths of two to four feet and could have severe consequences for anyone involved.
New wind slabs have formed on leeward terrain. These slabs will be sensitive to backcountry riders and skiers today and have a slight potential to fail naturally. These slabs will release as soft slabs and could have depths of one to two feet.
( Discussion is generated from the previous day's afternoon forecast. )Another round of snow arrives on a northwest flow late tonight with sixteen to twenty inches possible in the next twenty-four hours for the Tetons and Salt River Ranges. Valley locations will also receive a good amount with twelve to fifteen inches possible in Star Valley and Jackson. The Togwotee area is forecast to receive eight to ten inches. West wind will average around twenty-five mile per hour with gusts to fifty on ridgelines in the Tetons with stronger winds to the south in the Salts. Expect wind speeds around thirty miles per hour there. Temperatures will rise slightly during this period from the single digits to the upper teens. Wind blown snow will add further stress to the weak layer deep in the snowpack while building slabs one to three feet in thickness. In places where the snowpack is thinner, the weak layer may be more reactive to additional loading. While there has been some time for the snowpack to adjust to the recent snowfall load, continued loading increases the risk of large to very large natural avalanches occurring on this persistent layer. The combination of fresh wind slabs that will be sensitive to human triggering combined with further strain on the deeper, persistent weak layer will keep the avalanche danger elevated again tomorrow. You can expect fresh wind slabs one to three feet thick plus the lingering concern of triggering a very large avalanche on the deeply buried facets. All forecast areas will have a Considerable danger rating at higher elevations. The danger rating will increase to Moderate on steep slopes at lower elevations.
