Avalanche Forecast

Archived

Jan 21st, 2019–Jan 23rd, 2019

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Vancouver Island.

Confidence

Moderate - Recent observations have built confidence. Freezing level uncertainty on Tuesday.

Travel & Terrain Advice

Rising freezing levels and rain below treeline and at treeline on Tuesday will cause the upper snow pack to lose strength. Be aware of changing conditions with elevation changes. Cornices will be more fragile as temperature rises and with added precipitation load. Do not travel above or below consequential overhangs or the slopes below them that may be affected.

Avalanche Summary

Very little activity observed/reported. A few small isolated size 1 wind slab avalanches were triggered with ski cuts on north aspects at 1500 m. These avalanches were initiated in the recent storm snow and were not very deep.

Snowpack Summary

Clear and calm nights have produced surface hoar development on all aspects and elevations. These weak feathery crystals have formed on top of 20-50 cm of our most recent storm snow which sits on top of an old strong melt freeze crust. This snow is bonding well and showing little to no signs of instability at that interface. Below this crust the mid and lower snow pack is well settled and dense.

Snowpack Details

Surface: Weak feathery surface hoar has grown on all aspects and elevations. Upper: Dry loose storm snow with several weak layers. Bonding well to old crust surface. Mid: Well settled. Lower: Well settled.

Past Weather

Friday and Saturday brought 20-50 cm of accumulation with highest totals above treeline and in the southern region. Strong winds associated with this precipitation created highly wind affected surfaces. Cool temperatures have prevailed and maintained snow quality with dry snow on all aspects above 1200 m. Recent clear calm nights in the wake of low pressure have created surface hoar and a drying of the upper snow pack.

Weather Forecast

MONDAY: Minimal precipitation, with light winds from the NW veering to strong SE in the afternoon. Freezing levels around 900 m. TUESDAY: 20-35 mm of precipitation with freezing levels spiking up to 2100 m in the afternoon. Winds strong to extreme from the south. WEDNESDAY: 5-10 cm with freezing levels dropping from their height on Tuesday to around 800 m. Winds moderate from the NW.

Problems

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.