Many close calls occurred this week, and very large avalanches are still human-triggerable.
Avoid all avalanche terrain during periods of high hazard.
Weak layers remain a concern, especially in north-facing terrain where snowpack depth is variable. Avoid steep and shallow rocky features where human-triggering is possible.
Storm snow and strong southwest winds have formed reactive storm slabs. Expect to find deeper and more reactive deposits on north- and east-facing slopes.
Storm slabs may step-down to deeper layers resulting in very large avalanches.
Rain-on-snow and warm temperatures can rapidly destabilize the snowpack.
Wet loose avalanches can trigger slab avalanches that fail on deeper snow or weak layers.
We expect avalanches to continue with wet and large slab avalanches being easy to trigger during this warm period.
Saturday, a very large persistent slab avalanche was snowmobile triggered near Wendy Thompson. Cornice fall in the Chilcotins also triggered a size 2.5 storm slab on a slope below.
Friday, skiers remotely triggered this very large persistent slab avalanche near Vantage Peak. Explosives produced four size 2.5 persistent slab avalanches on NW alpine slopes.
10 to 15 cm of new snow has been redistributed into deeper deposits on north- and east-facing slopes by moderate to strong southwesterly winds. Below treeline, this fell as rain so expect to find moist surface snow. Warm temperatures today may moisten surfaces at all elevations.
A melt-freeze crust on southerly slopes up to 2000 m exists about 60 cm deep. This sits over 80 to 150 cm of settled snow.
The early March weak layer of facets or surface hoar on a crust is now down 100 to 170 cm and is present on all aspects except high north-facing slopes. Very large avalanches (size 3 to 3.5) were reported on this layer this past week.
Weak layers formed in mid-February and late-January are now buried 180 to 250 cm deep.
Monday Night
Cloudy with 5 mm, falling as snow above 1500 m. 20 to 40 km/h southwest ridgetop winds. Treeline temperature -2 °C.
Tuesday
Cloudy with trace rain. 30 to 50 km/h southwest ridgetop winds. Treeline temperature 2 °C.
Wednesday
Partly cloudy with trace rain. 20 km/h south ridgetop winds. Treeline temperature 4 °C.
Thursday
Mostly cloudy with up to 5 mm, falling as snow above 1500 m. 20 to 40 km/h southwest ridgetop winds. Treeline temperature 0 °C. Freezing level drops to 1500 m.
More details can be found in the Mountain Weather Forecast.
