Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible - Likely
- Size
- 1–2
This problem is generally found in specific pockets in the alpine and exposed treeline slopes. Be vigilant for signs of instability such as whumphing or cracking.
In many areas of Jasper, the snowpack has doubled since March 8th with 80cm of new snow. This is significant volume. If a slope did not release naturally already, one should be very suspicious for human triggering. Our neighbors to the South have had recent avalanche fatalities.
This problem is generally found in specific pockets in the alpine and exposed treeline slopes. Be vigilant for signs of instability such as whumphing or cracking.
This avalanche problem is associated with a weak facet and crust layer buried at the end of January approximately 70cm down in sheltered areas. This includes a crust layer formed in early March below the recent storm snow which is prominent on solar aspects.
Well developed facets and depth hoar at the bottom of the snow pack can produce large avalanches. Several big avalanches released during and immediately after the March 7th storm. Be suspicious of any slopes that have not released naturally.
Sunday's Maligne Bald hill patrol noted one size 2 slab in the alpine SE aspect which may have been 2 days old. Saturday's Icefield patrol noted one size 2.5 across the valley from Mt Wilson and a couple of recent slides on Mt Lecturn. Friday's avalanche cycle produced many alpine avalanches up to size 3 running to treeline. These avalanches had wide propagation and connected through multiple terrain features.
20-30cm cm arrived on Thursday which adds to our total of 70-80cm since March 9th. Below the fresh snow, the snowpack is complex having multiple crusts and facet layers. The bottom of the snowpack is facets and depth hoar.
Monday will be sun, flurries, -8 °C, and light SW winds. Tuesday and Wednesday will be similar conditions but slightly colder at -17 to -10 °C.