Avalanche Forecast
Regions: Banff Yoho Kootenay.
More wind slab development at upper elevations will keep the avalanche hazard elevated Saturday.
Uncertainty exists around the persistent layers in the snowpack, as some deep releases have occurred recently and lowered our confidence.
Weather Forecast
5 to 10cm of snow starting Friday night into Saturday, this new snow will be redistributed by moderate to strong wind in the alpine. These winds are expected to tapper throughout the day. Temps will stay cool this weekend with freezing levels remaining at valley bottom.
Snowpack Summary
Up to 30cm of new snow now buries a crust up to 1800m, higher on steep solar aspects. New wind slab growth in the alpine down into tree line. Several persistent layers exist in the mid to lower snowpack and have been responsible for several large avalanches. These layers will remain a concern for some time due to their uncertainty.
Avalanche Summary
A loose dry avalanche cycle occurred with increased winds Friday. Over the past week we have observed and received reports of several cornice failures and small slab releases digging down and triggering deep releases up to size 3.5.
Confidence
Avalanche Problems
Wind Slabs
30cm of new snow since Thursday with moderate to strong winds have formed new wind slab in alpine and open tree line terrain. Though we have limited observations of avalanche activity, we expect this problem to be reactive over the next few days.
- Be careful with wind loaded pockets, especially in steep confined alpine terrain.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Persistent Slabs
Several deeper releases occurred over the past week (see avalanche table). There is a lot of uncertainty as to which layers within the snowpack these slid on. We will be monitoring this in the coming days to see if it continues.
- Pockets of persistent slabs linger on alpine lee features.
- Pay attention to overhead hazards like cornices which could trigger persistent slabs.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3.5
Loose Dry
Anticipate loose dry activity in steep alpine terrain, especially in confined or exposed terrain features where even a small sluff can have severe consequences.
- If triggered dry loose point releases can form deeper deposits in terrain traps.
- Be careful of loose dry power sluffing in steep, confined or exposed terrain.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Likely
Expected Size: 1 - 1.5