Use caution in wind loaded terrain and on big features.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
SUNDAY: Cloudy with flurries, 5 cm of snow, freezing level at 1000m, strong westerly winds.MONDAY: Cloudy with flurries,10 to 15cm of snow, freezing level around 1200m, and winds moderate from the South.TUESDAY: A break in the weather, cloudy with sunny periods, freezing level may go to 1200m, wind from the South West.
Avalanche Summary
No reports of avalanche activity in the Sea to Sky region, (yet..), probably because the storm is just beginning. Expect wind slab activity and cornice failures with the current weather pattern and increased loading. Solar aspects will be come active when the sun comes out.
Snowpack Summary
20cm of recent precipitation on a variety of crusts and old surfaces. Surface hoar and facets in sheltered locations from the recent clear weather. Moderate to strong south west winds will redistribute the storm snow into wind slabs on the lee sides of ridge tops. A facet/crust layer buried in mid-March has been producing hard and sudden results in snowpack tests. This remains a concern in the region due to it's potential to produce very large avalanches. Cornices are also a concern these days. A cornice failure may trigger a large destructive avalanche.
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.