Storm Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1–2
Avalanches are most likely at upper elevations and on leeward slopes where you find recent wind-loading. However, wind-stiffened slabs may be hidden under more recent snow. Use a pole or probe to feel for stiffer snow in suspect terrain. You may also be able to trigger avalanches in the recent snow on wind-sheltered slopes above 4,500ft.
Watch for "red-flag" signs of instability, such as recent avalanches, blowing snow, and cracks shooting through the snow. Use quick tests to check how easily the upper 2 feet of snow slides. If you see it slide easily, especially on a crust, consider this another "red flag." If you see these signs of instability, reduce the risk of an avalanche by sticking to low-angle areas, under 35 degrees. Additionally, avoid steep slopes beneath corniced ridgelines and wind-exposed terrain.
(12/20/2025) An example of a simple "switchback test." This cut corner produced a long crack that "popped with energy." Snoqualmie Pass, Alpental Valley