Yesterday, strong southerly wind and new snow built wind slabs that you could trigger today. Look for signs of wind loading like shooting cracks in the snow's surface or drifts. Warming temperatures and periods of sunshine will make avalanches more likely this afternoon. Triggering an avalanche on deeper layers remains possible, particularly in specific areas of this zone (Wyoming Range) or at lower elevations where the weak layers lie closer to the surface.
You're most likely to find and trigger wind slabs at ridgetops in the upper elevations but there were reports of strong wind speeds building drifts at middle elevations down to 8,000'. These could be one to two feet thick or possibly thicker beneath steep terrain features and couloirs. expect these slabs to become more reactive on sunlit slopes if skies clear this afternoon.
The Greys River zone is an expansive forecast area that contains a diverse snowpack right now. The most concerning part of the snowpack is the layer that was buried Feb 18. Avalanche activity continues on this layer that is unpredictable and potentially large in size. the remotely triggered avalanche in the Wyoming Range is an attention-getter. Much of the Greys River zone, the Ssalt River RAnbge, the Palisades and even portions of the Snake River Range are deep and have generally good stability. Shallower areas of those zones and essentially all of the Wyoming Range have poor stability with slabs 1-3' thick over weak layers in various states faceting. Riding in the Little Greys on Tuesday was great on lower angled slopes but stepping off the sled and punching through to the ground in facets was a good reminder to avoid steep slopes.
Recent avalanche activity has occurred on this layer in areas with a thin, shallow snowpack such as the Wyoming Range (Dry Creek Lake, Hoback Peak).
(3/7/2023)
This avalanche was triggered remotely by the skiers on the rib well to the right of the start zone.
Photo: Dan Janjigian
Note that the Greys River zone persistent slab problem is now painted on all aspects and elevations due to the widespread distribution of this layer and the continuing avalanche occurances. The snowier portions of this zone have buried the layer more deeply which leads to less reactivity in the layer. Areas with a thinner snowpack such as the Wyoming Range or lower elevations across the zone have greater instability.
