Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Although this new snow will fall on the heavy or "wetter" end of the spectrum, the forecasted strong winds will certainly be enough to move that snow around. In some areas you may find 3-5 times more snow deposited from wind than actually fell from the sky, especially in start zones such as below ridgelines and along terrain features that promote cross-loading. As new snow accumulates throughout the day, wind slabs will build in proportion to the snow totals we receive.
On Tuesday at Ball Butte, warm temperatures and varied surface conditions reigned supreme. Although most surface snow was sun or wind affected, I found one pocket of preserved surface hoar on a steep shaded slope at 8,000 ft. At lower elevations, I was unable to find preserved SH and it appeared that even shaded slopes were affected from the warm temperatures and/or light rain that reached these elevations. All of this means that on shaded slopes near and above treeline, new snow may land on weaker surface snow. In these areas, slabs could be more reactive, particularly where soft, preserved snow exists beneath the fresh load. Expect heightened sensitivity where wind drifted snow overlies lighter density surface grains.
With wind slabs, there are a few different warning signs, that aid in predicting and understanding their presence. Smooth, pillowy, or rippled surface textures are a great visual clue, as well as snow plumes blowing off ridges or blowing snow filling in the skin track. Additionally, shooting cracks and collapsing snow are great indicators of a current wind slab problem. If you are unsure of the snow stability, it is a safer bet to avoid steep slopes, stay below treeline, or keep on windward terrain.