The combination of recent snow, wind, and buried weak layers make human triggered avalanches possible today. Steep and rocky areas that have been wind affected on north through east through south aspects are the most likely areas to trigger a slab. Monitor the wind direction and pay attention to signs of instability such as cracking within drifted snow or audible collapsing of the snowpack. With the sun poking out many slopes will seem inviting today but be mindful of poor snowpack structure in many locations.
Wind slabs (both soft and hard) are possible at the upper elevations today, with depths around 12 inches.
Up to 8 inches of snow has fallen at the upper elevations in the Togwotee zone over the last 4 days. This snow has largely been low density and is readily available for transport. Monitor the wind direction and look for blowing and drifting snow.
Weak, sugary snow is buried 1-3 feet deep below the surface of the snow. These layers formed from cold, dry periods that occured in November and early December and are widespread. Avoid steep and rocky areas that are wind effected where triggering a slab is more likely.
(1/1/2023) R3D2 on Angle mtn. Photo: Andrew Newman
Weather Synopsis
The Tetons have picked up 1-4 inches in the last 24 hrs, with the Greys picking up around an inch and Togwotee receiving 1-2 inches. Winds have been light to moderate at ridgline, with average speeds in the 10-15 mph range and directions out of the S through W. In the last 4 days the mountains of western Wyoming have picked up 6-18 inches of snow with light to moderate winds.
Yesterday's atmospheric circulations were somewhat strange, with western Wyoming sitting in between stronger flow to the north and south. This allowed for small scale orographic effects to dominate, resulting in variable new snow amounts throughout the Tetons. A weak trough began to impact western Wyoming on January 5th. Prior to this the forecast area was under primarily NW flow as a closed low system sat over southern Minnesota.
A weak ridge is in place for the time being but it won't last long. The next pulse of moisture looks to be showing up Sunday night into Monday ahead of a larger trough.
Recent Avalanches
The most recent natural avalanche cycle followed on the heels of tropical moisture in a SW-W flow that hit Togwotee from December 27- January 1. No human triggered avalanches have been reported recently.
Snowpack Summary
Current snow surfaces are composed of low density snow that has settled with some graupel from January 5 mixed in. In wind affected areas the surface of the snow has turned into upside down wind slabs.
Snow depths are approaching 1-1.5 meters at upper elevations in the Togwotee area. The top half of the snow pack is composed of new, decomposing, and wind packed snow. The bottom half of the snowpack is composed of crusts and advanced facets that are in excess of 2mm in some locations. All of the snow from November and October has faceted, with the October snow taking on the form of depth hoar.
