Avalanche Forecast
Regions: Little Yoho.
While human triggering is likely at treeline and above, it is still essential to manage your exposure to avalanche terrain at lower elevations: natural avalanches reaching valley bottom trails are still considered possible.
Weather Forecast
Expect 5 to 10 cm to arrive starting Friday night through Saturday as winds shift from South back to West and climb into the moderate range. Temperatures will cool to -15C values in the ALP Sunday morning with some clearing expected before the cycle repeats: winds shift back to a light South flow bringing warming and a bit more precip for Monday.
Snowpack Summary
100cm of dense, rounded snow comprises the upper half of the snowpack and sits on a variety of different foundations depending on location. In shallow areas (eg: Field ice climbs) the base is weak depth hoar. In deeper areas (eg: Little Yoho Valley), the base is rounded and stronger. Shears persist in the deep facets, and within the storm snow.
Avalanche Summary
The natural activity has begun to diminish over the last few days however daily reports of activity continue to come in with a sz 2.5 reported on the NE aspect of Mt Fatigue today near Sunshine. It appears to take only very small inputs of sun, wind or precip to trigger natural events and artificial / human triggering should be considered likely.
Confidence
Intensity of incoming weather systems is uncertain on Friday
Avalanche Problems
Persistent Slabs
Natural activity is starting to taper, but the snowpack is considered very suspect right now. Large avalanches initiating TL and above have recently run to valley bottom with crowns up to 2m + deep and several hundred meters in length.
- Be wary of slopes that did not previously avalanche.
- Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 3 - 4
Wind Slabs
Wind transport was significant Thursday and has continued to a lesser extent Friday. Expect the fresh slabs that have formed at higher elevations to be easy to trigger. Expect the new growth on cornices to be fragile.
- Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood: Likely - Very Likely
Expected Size: 2 - 3