Avalanche Forecast
Regions: East Island, North Island, South Island, Vancouver Island, West Island.
Heavy loading from new snow, wind, and rain will create very dangerous avalanche conditions. Avoid avalanche terrain and exposure to overhead hazard.
Confidence
Moderate
Avalanche Summary
On Thursday, skiers triggered several storm slab avalanches (size 1-2) from alpine and treeline terrain near Mount Arrowsmith.
We suspect a natural avalanche cycle will occur on Thursday night and into Friday as freezing levels rise. Storm or persistent slab activity can be expected where the new snow remains dry. As snow transitions to rain, a widespread wet loose avalanche cycle is expected.
Snowpack Summary
Overnight snowfall will continue on Friday with 20 to 50 cm of new snow expected. Precipitation will transition to rain on Friday, soaking the upper snowpack. In the high alpine, snow may remain dry and will be redistributed by strong southerly winds.
A weak facet/crust layer can be found down 50 to 100 cm. The remainder of the snowpack is strong, with numerous hard melt-freeze crusts.
Treeline snow depth ranges from 100 to 180 cm. Snow depth diminishes rapidly at low elevations where there has been more rainfall.
Weather Summary
Thursday Night
Cloudy with snowfall, 15 to 40 cm of accumulation. Alpine wind southeast 40 to 60 km/h. Treeline temperature rising to -4 C.
Friday
Cloudy with snowfall turning to rain in the morning. 10 to 50 mm of precipitation, heaviest on the west island. Alpine wind south 50 to 80 km/h. Treeline temperature rises to 3 °C, freezing level rising to 2300 m.
Saturday
Cloudy with light precipitation falling as rain below 1800 m, up to 5 mm. Alpine wind south 15 to 30 km/h. Treeline temperature 1 °C, freezing level around 1800 m.
Sunday
Cloudy with light precipitation falling as rain below 1800 m, up to 5 mm. Alpine wind south 15 to 30 km/h. Treeline temperature 1 °C, freezing level around 1800 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for rapidly changing conditions during periods of heavy loading from new snow, wind, or rain.
- Storm slabs in motion may step down to deeply buried weak layers resulting in very large avalanches.
- The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
Avalanche Problems
Storm Slabs
Where the storm snow remains dry reactive storm slabs can be expected, particularly in wind-loaded terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2.5
Persistent Slabs
A weak layer of facets overlying a crust exists down 50 to 100 cm. Heavy loading from new snow, rain, and wind may cause this layer to become active, producing large and consequential avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1.5 - 3
Loose Wet
As snowfall transitions to rain and soaks the upper snowpack, expect wet loose avalanches to occur in steep terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2