Bridger Teton Avalanche Center
WESTERN WYOMING AVALANCHE ADVISORY
Issued on Sat January 21, 2017 6:29 PM
Western Wyoming was under mostly cloudy to overcast skies as a weak, Pacific disturbance moved into the area. This weather system produced periods of light, scattered snow showers which modestly picked up in the late afternoon. Mountain temperatures rose into the mid to upper teens as the valleys climbed into the mid 20s. Southerly ridgetop winds at 5 to 15 miles per hour this morning veered to the west and increased to 15 to 30 miles per hour in the afternoon.
Late in the day on Friday, a skier triggered a small pocket of soft slab south of the Jackson Hole Mountain Resort. This slide occurred in very steep, northeast facing terrain at an elevation of around 10,300 feet. Shallow loose snow sluffs, which released naturally, were also reported in steep, upper elevation terrain in Grand Teton National Park. These slides were running on recently develop near surface facets, surface hoar and hard sun crusts. The loose, light density snow that has fallen over the past few days is readily available for wind transport.
FORECAST FOR Sunday, January 22, 2017
Periods of light snowfall will continue overnight before a brief lull takes place. By late afternoon, a more significant Pacific weather system will begin to impact the region. Overnight lows in the mountains will be near 10 degrees before rising into the upper teens during the day. Westerly ridgetop winds will range from 15 to 25 miles per hour.
The general avalanche hazard could increase to Moderate in the Tetons depending on the amount of new snow and the strength of the winds. New soft slabs, along with loose snow sluffs, could be triggered by backcountry travelers in steep, avalanche prone terrain above 9,000 feet. These slabs are building just above well-developed sliding surfaces and weak, faceted snow.
In the Greys River and Togwotee Pass forecast zones, the lingering chance of triggering deep persistent slab avalanches failing on weak snow near the base of the snowpack will keep the hazard at Moderate. New soft slabs and loose snow sluffs, similar to those in the Tetons, could also be triggered by skiers and riders. This avalanche activity will be more likely to occur down south where snowfall amounts are expected to be greater.
TREND FOR Monday, January 23, 2017 AND Tuesday, January 24, 2017
The storm system that will begin to affect the region on Sunday will last through Monday and possibly into Tuesday. The general avalanche hazard will continue to increase as new soft slabs gain depth and volume.
For further information call 307-733-2664
To report an avalanche observation call 307-739-2607
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