6am update: Heavy overnight snowfall has increased avalanche danger to HIGH at upper elevations. Some areas will continue to experience heavy localized snowfall throughout the day due to convection. Seek out sheltered terrain away from the wind to enjoy the best turns.
A crust formed in mid-January can be found down 90 to 130 cm. In areas around the Coquihalla, facets can be found sitting on the crust. This layer is of greatest concern with large triggers, such as a cornice fall, or by first triggering a smaller avalanche that could step down to this interface.
Reactive storm slabs are likely, especially on leeward slopes where wind/snow loading builds deeper slabs. In many areas, this new snow may be bonding poorly to the underlying surface and storm slab reactivity may persist for longer than is typical.
Watch for heavy localized snowfall today on west and northwest-facing slopes.
On Tuesday, a few wet loose avalanches up to size 1 were reported below treeline.
On Monday, one size 1.5 natural storm slab was observed from a distance on a steep treeline convex roll, and a natural glide slab released size 2 from a south aspect at 1600 m and ran 300 m in length.
On Friday, natural and human-triggered storm slabs are likely. Storm slab reactivity is expected to persist for longer than is typical due to the weak surface they are sitting on.
Up to 10 cm accumulation overnight will add to the 20 to 35 cm that fell yesterday. New snow should begin to settle on the 30 cm of settling snow that fell last weekend. The new snow may have a poor bond to the underlying stiff wind slabs and faceted snow formed by recent cold temperatures.
A melt-freeze crust formed in mid-January is buried up to 100 to 150 cm deep. In some areas, small faceted crystals can be found above the crust. This layer was reactive a week ago. The snow below this layer is well consolidated.
Snowpack depths are just below seasonal averages. Total amounts range from 150 to 300 cm at treeline, but decrease significantly below 1500 m.
Thursday Night
Cloudy, up to 10 cm accumulation, winds southwest 20 km/h gusting to 50, treeline temperatures -8 °C.
Friday
Cloudy with late-day sunny breaks in some areas, 8 cm accumulation with some west-facing slopes receiving up to 20 by the end of the day, winds southwest 20 km/h gusting to 50.
Saturday
A mix of sun and cloud, trace accumulation, winds southeast 30 to 30 km/h, treeline temperatures -5 °C, and freezing level climbing to 1200 m.
Sunday
A mix of sun and cloud, trace accumulation, winds southeast 15 km/h, treeline temperatures -5 °C.
More details can be found in the Mountain Weather Forecast.
