Storm Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1–2
Significant snow accumulations are likely overnight and Monday from a significant storm that will favor the eastern slopes of the Cascades. The Wenatchee and Chelan Mountains may pick up over a foot of new snow, with lighter accumulations near the crest. Newly formed storm slabs may be widespread and easy to trigger. Look for signs of instability such as recent avalanches, shooting cracks, or collapsing. You can use quick hand pits and small test slopes to identify storm interfaces and observe how the new snow reacts. Observations from the zone are limited, but a report from the Enchantments indicated widely variable surfaces that will make it possible for adjacent slopes to have different avalanche conditions. It will be best to choose low-angle slopes and avoid steep terrain features while this storm runs its course.
Shifting and gusty winds will likely blow this new snow around, but it will be hard to pin down one aspect where wind loading is most likely. Therefore, use visual clues to identify areas where wind slabs are forming. Look for actively blowing snow, textured surfaces, or drifts around rocks and trees.
Rough surfaces and a thin snowpack limit avalanche potential at lower elevations throughout the zone. Still, the snow has been piling up for the last few days, and you may be able to trigger small avalanches in the new snow, even at lower elevations. Use caution in terrain where a small avalanche could push you into rocks, trees, or other obstacles.
(12/21/2021)
Shooting cracks like this one in the new snow are a red flag sign of instability.
Photo: Matt Primomo