Storm Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1.5–2.5
The final wave in this week's storm parade will have the final say. With daytime snow totals expected to exceed single digits, both wind and storm slab instabilities will overlap. Larger and more consequential slabs of wind deposited snow will grow unstable first. These locations exist beneath ridgelines, on the sidewalls of gullies, and around rock outcroppings. Watch for continued snow transport and remain suspicious of slopes presenting rippled or textured surfaces that appear lens or dune shaped. Fresh wind lips and cornices both point towards slopes to avoid.
Dial back your slope angles in terrain holding over 6 inches of fresh snow to manage the risk of storm slabs. Instabilities will be greatest during or directly after active snowfall. Which, in this case, peak storm will occur over the morning and midday hours. Gauge this problem by observing, feeling, and testing for cohesive snow and shooting cracks underfoot or machine on small test slopes.
Intermittent weather and a graupel layer have developed interfaces within the recent storm snow which avalanches could fail on. Dig down and test these layers to gauge the snow’s reactivity. The weight of a triggered wind slab could release the surrounding storm snow and result in a much larger and consequential avalanche.
(1/20/2024)
An example of a storm slab avalanche that may be encountered today, as snow accumulates below treeline
Photo: Samuel Clairmont