The storm and avalanche cycle continue. Time to scale back objectives to low angle conservative terrain.
Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
Overnight and Wednesday: Another pulse of moisture from the Pacific is expected to bring 5-10 cm of snow above 1400 metre elevation combined with very strong Southwest winds. Fernie and the Southeast of the region may see enhanced snowfall of 10-20 cm by morning. Winds should shift to moderate Northwest after the storm has passed.Thursday: Overcast with a mix of flurries and possibly some sunny breaks. Freezing level rising briefly up to about 1300 metres.Friday: Overcast with light winds and periods of light flurries.
Avalanche Summary
We continue to get reports of accidentally triggered and remote triggered avalanches. See the bottom left of the bulletin page for a list of reported avalanches for this region. I suspect that the storm slab is settling and becoming more cohesive. Forecast new snow and wind loading are expected to add a new load to this recent storm slab that may increase the sensitivity to human triggers and may result in natural avalanches.
Snowpack Summary
Not much change, about 5-8 cm more snow added to the following comments. Another 20 cm of new snow has added to the recent storm slab that is now about 75 cm thick and is settling into a cohesive slab (one finger resistance). The layer of weak facetted (four finger resistance) snow that is below the storm slab has been reported as widespread on all aspects and at all elevations across the region. This is the classic firm slab over soft and weak layer that can allow for wide propagations and remote triggering. This problem may persist for days after the storm or even weeks. The next forecast storm on Tuesday night may overload the weakness and cause another natural avalanche cycle. Regardless, it will continue to load above the weak layer priming conditions for large slab avalanches. The mid snowpack is strong and supportive. A deep persistent layer of facets and depth hoar near the base of the snowpack has remained dormant to this point, but may become a concern with additional load and stress on the snowpack.
Problems
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.