Avalanche Forecast
Regions: Little Yoho.
An avalanche cycle is expected over the next 24 hours as a reasonably intense storm passes through the area. Large avalanches on the persistent layers would not be surprising with cornices, windslabs and even loose dry avalanches as possible triggers
Weather Forecast
A low is passing over the Jasper area early Friday afternoon with a cold front to follow into the forecast region. Heavy snowfall combined with strong SW winds in the alpine are expected to create rapid loading. Temperatures have reached their peak Friday afternoon and can be expected to cool to -10C values at Treeline for Saturday morning.
Snowpack Summary
40cm of soft snow overlies a well-settled and firm mid-pack. Near treeline, concern remains for a facetted layer that sits in the lower third of the snowpack, and an old surface hoar layer down about 50-70 cm that has recently produced sudden planar shears. Deeper snowpacks to the west of the Wapta Icefields have the strongest snow.
Avalanche Summary
The forecast team on Mt Field today witnessed what was likely a cornice failure off Mt Wapta resulting in a pretty decent cloud seen despite poor visibility at around noon as the storm just started to take hold.
Confidence
Intensity of incoming weather systems is uncertain on Friday
Avalanche Problems
Wind Slabs
With strong winds and fresh snow, new wind slabs and sensitive cornices are forming. If triggered these may step down to the deep persisitent layers.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
In deeper snowpack areas found in the alpine, there is decent bridging over weaker persistent layers. Use caution in thin areas in the alpine as well as at treeline and below where human triggering remains possible.
- Use conservative route selection, choose moderate angled and supported terrain with low consequence.
- Minimize overhead exposure; avalanches triggered by wind loading may travel long distances.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3
Loose Dry
In the short term expect loose snow to fail easily in steep terrain. Use caution in confined features or around terrain traps like cliffs. This could be especially true on the ice climbs around the Field area.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 2