Bridger Teton Avalanche Center
WESTERN WYOMING AVALANCHE ADIVSORY
Issued on Mon March 10, 2014 7:07 PM
A complex winter trough is slowly moving east. Moisture embedded in this system brought an inch or two of new snow to the higher elevations and rain showers to the valleys early this morning. Skies were then mostly cloudy until mid afternoon when valley rain and mountain snowfall moved into the region from the west. Two to four inches of snow fell at the higher elevations during the late afternoon hours.
Temperatures were above freezing in the valleys. In the mountains they warmed into the upper 20s to mid 30s and were dropping into the 20s later in the day as colder air began to seep southward from Montana. Winds along the higher ridge crests were west-southwesterly at 20 to 30 with gusts to 50 miles per hour.
At the mid and upper elevations old snow surfaces were crusty on southerly aspects and comprised of loose dry snow on shaded aspects. At the lower elevations snow surfaces were comprised of wet loose snow.
Today we received a report that a six foot deep hard slab released naturally on a southeast aspect of East Angle Mountain west of Togwotee Pass on Saturday. Deep slab avalanches were remotely triggered by skiers in the Southern Teton Range a week ago. We believe there may be some areas on both sides of the Continental Divide in the Togwotee Pass area where these deep hard slabs could still be triggered by humans. In the Teton Area we believe these slabs are unlikely to be triggered by humans except perhaps in isolated areas. Due to our uncertainty our recommendation continues to be to make conservative terrain choices, especially during and after the current storm period. We have no reports of recent deep slab avalanche activity in the Greys River/Southwest Trails Area, however most of the large destructive deep slab avalanche activity that has been observed in February occurred in that forecast area.
Dense surface slabs have caught and carried several skiers and caused serious injury to one person during the past week.
FORECAST FOR Tuesday, March 11, 2014
Colder air will move into the area overnight. Snow levels will fall to the valley level by morning. A slow clearing trend will occur on Tuesday with additional but diminishing mountain snowfall. Skies should begin to clear later in the day. Temperatures in the mountains will drop into the teens overnight and rise into the 20s during the day. Valleys temperatures should drop below freezing overnight and rise into the low to mid 30s during the day. West winds will veer to the northeast. Winds speeds of 25 to 35 with higher gusts will accompany the snowfall.
On Tuesday new wind slabs that formed overnight are likely to be easily triggered by humans on steep wind loaded slopes and could attain depths of one to two feet. In areas with poor snowpack structure the potential for humans to trigger dangerous deep hard slabs will continue to be a concern. The general avalanche hazard is expected to be CONSIDERABLE in areas with poor snowpack structure (Greys River/Southwest Trails and Togwotee Pass/Continental Divide Areas) and MODERATE in locations where the threat of deep instabilities is limited to isolated areas.
TREND FOR Wednesday, March 12, 2014 AND Thursday, March 13, 2014
Colder and dryer conditions will prevail as a high pressure ridge builds over the region. The avalanche hazard will slowly decrease.
For further information call 307-733-2664
To report an avalanche observation call 307-739-2607
SPONSORS: Togwotee Mountain Lodge, Box Y Ranch, Jackson Hole Mountain Resort, Brooks Lake Lodge, Wyoming State Trails Program, Bruce Hayse M.D., Wyoming Public Television KCWC, Storm Show Studios, Skinny Skis, Chippy's Kitchen and Catering, Apex Real Estate and Property Management, Teton Gravity Research, Snow King Resort, Idaho National Laboratory , Jackson Hole Mountain Guides, Grand Targhee Resort, DeFazio Law, Eric Balog, Twenty Two Designs, Jackson Hole Ski Atlas, Jackson Hole Snow Devils, Stewart Johnson, CPA, Exum Mountain Guides, Four Pines Physical Therapy, Backcountry Access, Grand Teton Floor & Window Coverings, Clif Bar & Company, Outdoor Research, Steve Romeo Memorial Fund, International Snowmobile Manufacturers Association, Voile and Danny Williams Architect