Bridger Teton Avalanche Center
WESTERN WYOMING AVALANCHE ADVISORY
Issued on Fri December 09, 2016 6:06 PM
Three to six inches of snow accumulated in Western Wyoming Thursday night and into the morning hours. After a brief lull, snowfall resumed around noon and intensified through the afternoon with heavy snowfall occurring by the evening. Mountain temperatures rose to near 20 as the valley climbed into upper 20s. Southwesterly ridgetop winds ranged from 20 to 30 miles per hour with gusts into the mid 40s.
Mountain temperatures at the beginning of the first snowfall event Thursday night were in the single digits and rose through the night. In the past 36 hours, temperatures at the higher elevations have warmed around 25 degrees. Storm totals as of Friday evening are around eight to ten inches in the Tetons and Greys River areas, and three to five inches of new snow has accumulated in the Togwotee Pass area during the same period. This snow fell onto snow surfaces that had faceted during the cold spell over the previous days.
FORECAST FOR Saturday, December 10, 2016
The National Weather Service has issued a Winter Storm Warning for Western Wyoming through 6 PM on Saturday. Strong westerly flow combined with ample Pacific moisture will bring another significant snowfall event to the region. Expect 12 to 24 inches of new snow in the mountains by Saturday evening. Strong southwesterly ridgetop winds at 20 to 30 miles per hour will accompany this snowfall. Overnight lows in the mountains will be near 20 before rising into the mid 20s during the day.
The general avalanche hazard is expected to rise to HIGH. As the day progresses, the chance of triggering newly developed soft slabs will increase and become very likely by the end of the day. These slabs, which could also release naturally, are forming on faceted snow and could reach depths of three feet by Saturday evening. In terrain that held snow from early October, deep persistent slabs are likely to release naturally or be human triggered. In the Tetons, these slabs could have depths ranging from four to six feet. Slab depths are expected to be in the three to five foot range in the Greys River forecast zone and around two to four feet deep in the Togwotee Pass area. TRAVEL IN AVALANCHE TERRAIN IS NOT RECOMMENDED WHEN HIGH AVALANCHE HAZARD EXISTS.
TREND FOR Sunday, December 11, 2016 AND Monday, December 12, 2016
Snowfall intensity will decrease on Saturday evening before increasing once again on Sunday, and periods of snowfall will continue into the beginning of the week. Dangerous avalanche conditions will continue.
For further information call 307-733-2664
To report an avalanche observation call 307-739-2607
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