Tetons

An Avalanche Warning has been issued beginning at noon as a strong winter storm is bringing significant snowfall and strong winds to the area. At the Mid and Upper elevations westerly winds have moved new snow to lee slopes and cross-loaded ridges and developed easily triggered soft slabs to a foot in depth. Slabs will grow in size through the day and become more sensitive to triggers with warming temperatures. Avalanches also have the potential to pull out deeper areas of the weak, faceted snowpack. The new snow rests on an unstable combination of weak, faceted snow and/or crusts. At the lower elevations the potential for humans to release sloughs on very steep terrain like ravines or road cuts will increase.

Snow is expected to increase in intensity overnight through Thursday morning, with periods of snow showers through the remainder of Thursday. West winds are to be strong with 20 to 35 mile per hour averages. Warm temperatures are to continue with mountain highs in the upper twenties expected. The general avalanche hazard is expected to be High. Backcountry travelers will be able easily trigger soft slabs in steep terrain and natural activity will be likely. The sensitivity and size of these slabs will depend on the amount of snowfall and wind received but depths could reach to three feet as the day progresses and once initiated are likely to entrain the underlying faceted snow. An Avalanche Warning is in effect for the period from 12 Noon on Wednesday, December 28, 2011 until Midnight on Friday December 30, 2011 for Yellowstone N.P – Absaroka Mountains – Teton and Gros Ventre Mountains – Wind River Mountains East and West – Salt River and Wyoming Ranges - Snake River RangesHeavy snowfall and strong winds will create dangerous avalanche conditions in the mountainous areas of Western Wyoming. Natural and human triggered avalanches are likely to occur. Travel in avalanche terrain is not recommended. Avalanches could impact roadways on Teton Pass and in the Hoback and Snake River Canyons.