Wind Slabs
- Alta montaña
- Límite del bosque
- Bajo el límite del bosque
- Probabilidad
- Possible
- Tamaño
- 1–2
Yesterday, southwest winds were strong, with gusts in the extreme category. In the evening, winds dropped to moderate, making for ideal conditions for wind slab formation. Complicating the situation is that winds have ranged from the south to west to north in the past 24 hours. Skiers and riders should watch for wind slab presence in specific and possibly widespread terrain features such as the leeward side of ridgelines, in avalanche path starting zones, in crossloaded gullies and chutes, and on rollovers. Wind slab avalanches will be more sensitive in steep terrain features. Although the dominant winds were from the south and southwest, a wind slab avalanche could be encountered on all aspects due to shifting winds and high wind velocities that tend to be redirected by smaller terrain features. For those looking to get out, today will be an excellent day to play it safe and stick to sheltered below treeline terrain.
Today, moderate winds and strong gusts are forecast for the region. On upper ridgelines, snow may be stripped by upslope and southwest winds, but in specific locations, drifted snow will continue to load, making for possibly large (D2) avalanches of 8-20" crown height. Upon entering the backcountry be conservative and observant; look for wind loading and test the reactivity of slopes by traveling a couple feet above existing skin tracks, conducting hand pits, and performing switchback assessments. Look to the ridgelines for the direction of spindrift and active loading. Finally, watch for cracking and shearing, and if slabs release with any cohesion, don't be afraid to back off and choose lower angle terrain.
The incoming snow and current wind transportation may be loading pre-storm slopes that were slick melt-freeze crust and hardened wind board. It is possible that these surfaces may make for ideal bed surfaces and increase the sensitivity and likelihood of wind slab and storm slab avalanches. Depending on the temperatures and associated timing, some of these slabs could be quite reactive to the weight of a skier or rider. Play it safe today and retreat if you see obvious signs of instability, such as shooting cracks, or if you get reactivity in any stability assessments. Hard snow over soft snow is a sign that slopes could release. Proceed cautiously, have a tour plan, spread out on the approach, and ski one at a time.