The winds today were a big issue and have built some touchy windslabs at ridgetop. Any windloaded terrain feature should be treated with great suspicion. We now likely have hard slabs sitting on top of a structurally weak base layer. (PJ)
Confidence
Fair - Timing of incoming weather systems is uncertain on Tuesday
Weather Forecast
The forecast indicates falling freezing levels to valley bottom for Monday. Winds will diminish to the light/moderate range from the NW and with some possible light flurries.
Avalanche Summary
A medium sized avalanche cycle was observed today in the Kananaskis and Highwood areas today. Strong to extreme winds were seen moving the recent storm snow stripped off of windward south and west facing slopes onto north and east aspects as windslabs. These slabs are overloading the unconsolidated lower pack including facets from November 5th. In one case today, an avalanche up to size 2.5 failed on these facets on the ground and ran full path to the creek
Snowpack Summary
High freezing levels (2300 meters) and warm temperatures are promoting very rapid settlement of the new storm snow into a more cohesive slab at all elevations and aspects The winds were the main culprit today with serious redistribution of the new snow into windslabs on lee features. We found evidence of buried windslabs in exposed features at treeline and the lower structure of the snowpack was typically soft, weak and facetted.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.