Hazard may change to higher than forecast with daytime warming on solar aspects. Cornices should be regarded with respect and suspicion.
Confidence
Good - Due to the quality of field observations
Weather Forecast
Light precipitation for this evening, then this weather system should be out of the Sea to Sky region by Sunday morning with another light pulse of weather on Sunday afternoon and into Monday morning. Clear skies and sunny conditions into next week. Daytime freezing levels are expected to be between 1000 and 1500 m for early part of next week, then climbing to 2000 by Wednesday.. Moderate southerly alpine winds are expected tonight, then light winds preominantly from the East..
Avalanche Summary
No recent reports of avalanches in the Sea to Sky region
Snowpack Summary
Up to 50cm of recent storm snow is sitting on a thin breakable crust that caps recent moist snow on rain crust buried last Saturday. Reports suggest this 5 cm thick solid rain crust exists up to at least 2200m. Strong southwest winds may have shifted these new accumulations into touchy wind slabs in exposed terrain. A facet/crust persistent weakness buried mid-March is down approximately 70-130 cm and is still producing hard but sudden results in snowpack tests. This remains the chief concern amongst avalanche professionals in the region due to it's potential for very large avalanches. Cornices are now large and a cornice failure might trigger a large destructive avalanche. Solar aspects will become active with daytime warming.
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.
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.