Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–2.5
Stiff, cohesive slabs of snow make it more difficult to impact weak, collapsible snow layers below and trigger a large avalanche. However, if you find the shallow spot on a slope steeper than about 35 degrees, you could trigger a wide-breaking avalanche that will be a challenge to escape. Places where the snowpack is less than about three feet deep below cliffs, close to rock outcrops, and near ridgelines increases your chance to get into trouble. Be aware of the terrain around you, and don’t get lulled into a false sense of safety if signs of unstable snow like shooting cracks or audible collapses are absent.
Day over day warming may produce loose wet slides on southerly-facing slopes. These small, generally harmless slides should stay confined to near surface snow that gets wet and sluffs above a crust. Those slides that travel long distances downhill have the potential to trigger a larger, more dangerous dry snow avalanche that breaks near the ground.