Regions
Vancouver Island.
A few small size 1 skier triggered wind slabs reported on North aspects between 1400 and 1500 meters.
Past Weather
10-15 cm of snow fell above the 800 meter mark combined with moderate to strong south west wind. In the wake of this small weather disturbance, clear sky and warm temps occurred on Sunday with freezing levels rising to 2000 meters during the later afternoon.
Weather Forecast
A ridge of high pressure will provide clear sky and sunshine for both Monday and Tuesday. Beginning late Tuesday a low pressure system to the north of the area will begin to move south bringing increasing south west wind and precipitation. **Monday:** No new precipitation Winds light from the South West , Freezing levels at sea level rising during the daytime to 1600 meters. Temps at 1500 meters up to 1 degrees.**Tuesday:** Trace amounts of snow, Winds light to moderate from the South West, Freezing levels 1000 meters. Temps at 1500 meters -3 degrees.**Wednesday:** 15 to 20 cm of snow , Winds moderate to strong from the South West, Freezing levels 900 meters. Temps at 1500 meters - 4 degrees.
Terrain Advice
Caution when transitioning into freshly wind loaded slopes.Avoid travelling both above and below cornices.Avoid solar aspect during periods of clear sky, warming and when snow surfaces become moist and unconsolidated.
Snowpack Summary
The upper snowpack surfaces consists of some wind loaded pillows on north aspects with south aspects seeing direct sun and warming followed by overnight cooling forming a crust that is supportive to skis. Two crust exist in the upper snowpack one at 30cms and the other at 100cms. Both of these crusts are producing results in the moderate to hard range and are currently not concerning as they are well bridged and protected from the dense layer above. However, expect these layers to produce results/ avalanches during a prolonged period of warmth or a large increase in load such as 30 to 100mm of water. Mid and lower snowpack is well settled and dense. Overall snowpack average depths range from 300cm to 600cm and are dependent on elevation and range location.
Snowpack Details
- Surface: Variable surface conditions, dependent of elevation and orientation.
- Upper: Two reactive melt freeze crusts exist at 30cm and 100cm.
- Mid: Well settled and dense.
- Lower: Well settled and dense.
Confidence
Moderate - Numerous field observations and good agreement between forecasts weather models for this area.
Problems
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.
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.
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.