Regions
Vancouver Island.
Confidence
High - Significant storm system confirmed to continue with weather models, lots of field data gathered.
Travel & Terrain Advice
Travel in any avalanche terrain is NOT recommended when the hazard rating is HIGH or above. Stick to in-bounds controlled terrain or low angled slopes in forested areas with only small openings. Avoid large wind loaded open slopes on north west-north east aspects at all elevation bands. Travel will be very difficult due to new snowfall accumulations so give yourself extra time to be home before dark and bring emergency overnight gear just in case. Be cautious of what is above you, do not to expose yourself to overhead large avalanche terrain. Now is not the time to ride the big lines!
Avalanche Summary
Control work on Mt Washington produced numerous size 1-1.5 soft slabs and a few size 2 with explosives. Ski cutting produced a few soft slabs and numerous loose dry avalanches.
Snowpack Summary
Significant (OK, LARGE) quantities of new snow have fallen during the previous forecast period and will continue to fall. This new snow seams to be bonding well to the old crust but shears or failures have been noted within the new storm snow.
Snowpack Details
Surface: Widespread new snow with wind slabs on lee slopes. Some isolated zones of exposed crust at ridge top. Upper: New snow gaining in density as it gets lower. Some storm shears noted in tests. Bonding well to the old buried crust. Mid: Well settled. Lower: Well settled.
Past Weather
Significant new snow for the entire forecast area. Approx 40 cm to the north, 80 cm in the east and a huge 150+ cm in the west. A short temperature spike Wednesday warmed the upper snow pack. This warming helped bond the new snow to the old crust below and has now cooled and tightened up. Now, more snow has fallen on top with a few density changes/shears, but seams to be relatively stable.
Weather Forecast
More, More and More new snow! Another 80 cm-140 cm are forecast to fall during this forecast period/over the weekend, with a large load Saturday night into Sunday morning. This new snow will be accompanied by strong south east-south west winds, so expect significant snow transport. Temperatures will continue to cool so the snow will be amazing.Fri: 18-40 cm of new snowfall, strong south east to south west winds, freezing levels 900 m-1200 mSaturday: 15-40 cm of new snowfall, strong south east to south west winds, freezing levels 700-1000mSunday: 40-60 cm of new snowfall, very strong to strong south east winds dropping to moderate, freezing levels 700-1000m
Problems
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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.