Wind Slabs
- Alta montaña
- Límite del bosque
- Bajo el límite del bosque
- Probabilidad
- Possible
- Tamaño
- 1–2
Northerly aspects near and above treeline that are shady, steep, and convex are the most likely places to encounter lingering instabilities. Approach with caution and abide to Mother Nature's warning signs like, shooting cracks, collapsing, and recent avalanches. A predominant south and southeast wind has been blowing at strong to moderate speeds over the past 48 hours. Wind slabs have developed on all west, north, and east-facing aspects at all elevations, being most pronounced near and above treeline. South and southwest aspects have experienced cross-loading. High-intensity snowfall accompanied these winds, providing ample ammunition for wind slabs to grow multiple feet in depth. Drifted locations will be on the leeward sides of ridgelines, beneath rock outcroppings, and in mid-slope depressions. Wind lips and cornices will point to the most dangerous slopes. Textured or stiffened surfaces indicate the presence of a wind slab. Trigger points will be near convex slope features and in areas where drifted snow has nestled among steep rock outcroppings. Over 2.5 feet of storm snow has fallen across the forecast region since February 4th. In that time, temperatures have trended from cool to warm, inverting the upper portion of the snowpack. A surface slab a foot and a half deep now sits above softer snow that fell on February 1st. Surface slabs consist of nearly three inches of water weight and a 4-finger density, giving it a supportable feel, while not giving any signs or clues of instabilities. This can be tricky and deceiving in high stakes terrain. Yesterday, no signs of recent avalanches or surface instabilities were observed. However, stability tests resulted in propagation multiple times on a storm interface 42cm (17") down from the surface. These results reflect that even though these layers may be difficult to penetrate, there is still a risk of finding the right weak spot with the right trigger. The best line of defense is to give the snowpack time to adjust to the new load before stepping out into steep terrain.