Rain heavily loads the snowpack, testing buried weak layers for the first time.
Conservative terrain selection is essential.
A weak layer from January, consisting of a melt-freeze crust with facets, is being tested by heavy loads from snow, rain, and warming. This layer could be a concern in the south and east ends of the region in shallower snowpack areas.
10 mm of rain and 3000 m freezing levels will destabilize the surface snow, making wet loose, and wet slab avalanches where storm slabs previously existed.
We expect a natural avalanche cycle to continue with rain destabilizing the snowpack.
On Saturday, a skier was involved in a storm slab avalanche, up to 60 cm deep, near July Mountain.
Thank you for sharing your observations to the MIN.
10 mm of rain is expected to create moist surfaces on all aspects and elevations. This falls on 40 to 60 cm of settling storm snow which was redistributed into deeper deposits on north- and east-facing slopes by strong southwest winds. This sits atop 80 to 100 cm of settled snow on north-facing slopes, and several thin melt-freeze layers on south-facing slopes.
A supportive crust is found below this, on all aspects except on high, north-facing alpine terrain. Snow is reportedly bonded well to it.
A weak layer of facets and surface hoar from February is now 90 to 150 cm deep and a layer of facets and surface hoar from late January is 110 to 190 cm deep. Some recent planar results were reported in the Manning Park area.
Monday Night
Cloudy with 5 to 10 mm, falling as snow above 2000 m, locally greater amounts near Chilliwack. 30 to 40 km/h southwest ridgetop winds. Treeline temperature 2 °C.
Tuesday
Mostly cloudy with up to 3 mm. 40 to 50 km/h southwest ridgetop winds. Treeline temperature 5 °C. Freezing level rising to 3000 m.
Wednesday
Partly cloudy with possible light rain, trace amounts. 30 km/h south ridgetop winds. Treeline temperature 7 °C.
Thursday
Cloudy with 5 to 10 mm. 40 to 60 km/h south ridgetop winds. Treeline temperature 4 °C. Freezing level drops to 1600 m throughout the day.
More details can be found in the Mountain Weather Forecast.
