Regions
Vancouver Island.
Confidence
High - weather models in agreement , numerous feild observations.
Travel & Terrain Advice
Use terrain features to avoid wind loaded areas. Avoid south aspect terrain if and when the sun comes out. Identify terrain traps and avoid as even a small avalanche will gain mass and pose a potential threat.
Avalanche Summary
Over the past three days , numerous natural avalanches observed up to size 1.5 loose and wet on all aspects and primarily at treeline and the alpine. Ski cutting and explosive testing revealed the upper snow pack to be touchy to skier traffic and easily trigger. Once trigger the wet upper snow pack easily gained mass and even a small avalanche posed a threat to mountain travellers.
Snowpack Summary
Heavy precipitation in the form of rain and wet snow has unconsolidated the upper snow pack. and the surface remains warm and wet. At treeline consistent observations found the snow pack to be at zero degrees down between 40 and 60 centimeters and foot penetration would vary between 45 centimeters and 100 centimeters dependent on aspect and elevation. The March 22 melt freeze layer is deep enough that it would only be trigger by a very large trigger and is not dormant but currently nonreactive. Below this a well settled and dense snow pack exists.
Snowpack Details
Surface: Wet and unconsolidated. Upper: Wet and unconsolidated. Mid: March 22 melt freeze crust suspect down over a meter. Lower: Well settled.
Past Weather
Warm and wet conditions persisted and the forecast areas received over 65 mm of rain fall. Winds where strong from the south east and during Saturday night freezing levels dropped to the 1300 meter mark and precipitation fell as wet snow.
Weather Forecast
Initially a weak ridge today will bring some relief from pacific warm fronts and some clearing with very little precipitation forecast and light wind. Beginning Tuesday a low pressure to the west of the region will bring to the area, heavy precipitation both in the form of rain and snow, and strong south east winds. Monday: no new snowfall. Temperatures 2 overnight rising to 6 mid day, winds light south east. Freezing level 1600 m rising to 2000 m mid day. Tuesday: 20 to 50 cm new snowfall 20 mm of rainfall. Temperatures 3 overnight rising to 4 by mid day, winds strong south east. Freezing level 1500 m dropping to 1000 m mid day. Wednesday: 10 to 20 cm new snowfall, 10 to 20 mm of rainfall. temperatures 0 rising to 1.5 mid day, winds light to moderate south east. Freezing level 1200 m.
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.
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.