Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Very Likely
- Size
- 1.5–2.5
Freezing levels are forecasted to be around 6000 ft but as with any forecast, they could end up being higher or lower, changing where precipitation will fall as snow or rain. Ultimately, regardless of whether you make it through the wet snow to reach dry snow somewhere higher up, conditions will not be safer. This atmospheric event (AR) will test buried weak layers at all elevations with added weight to the snowpack. Areas further west in the zone will receive higher snow totals, making conditions especially precarious in these areas.
Persistent slabs can break in surprising ways and wider than expected. You will be more likely to trigger a slide in wind-loaded areas, so be on the lookout for signs of wind transport. Clear signs of instability are cracks shooting from your skis or machine, collapsing (whumpfing), and recent natural or triggered slab avalanches. The best way to manage this problem while we wait for the snowpack to adjust to its new load is to avoid avalanche terrain. This includes where avalanches can start, run, and stop.
(2/21/2025)
A small skier triggered slab avalanche made clearly visible the two weak layer interfaces in the snowpack right now.
Photo: Payton Schiff