Avoid sun exposed slopes and overhead cornice hazard this afternoon as warm temperatures and solar input continue to weekend the snowpack.
Weather Forecast
Sun and warm temperatures will have a profound effect on the snowpack today. Freezing levels will rise this afternoon to around 2800m, bringing warm air high in to the alpine. A pacific frontal system arrives later this evening with wet flurries, strong south winds and slightly cooler temperatures. Up to 20cm of wet snow is expected for Saturday.
Snowpack Summary
Temperatures remained warm overnight, leading to a poor refreeze. 10cm of recent snow in the alpine overlies a sun crust on solar aspects and wind slabs and crusts on shaded slopes. Strong southerly winds have formed new wind slabs. Crusts in the top 20cm are weakening with continued warm temps and triggering of deeper layers is possible.
Avalanche Summary
A natural cycle of loose wet avalanches was observed yesterday in the highway corridor, up to size 2.5. Warm temperatures will continue to destabilize the snowpack throughout today. Yesterday skiers reported feeling a large whumph on the approach to Little Sifton Col, prompting the group retreat.
Confidence
Intensity of incoming weather systems is uncertain
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.