Recent snowfall resupplied a pair of avalanche problems affecting the region. Be mindful of avalanche danger increasing in sync with daytime warming.
Weather Forecast
Wednesday night: Cloudy with clear periods. Light east winds.Thursday: A mix of sun and cloud. Light east winds shifting northeast. Alpine high temperatures around -1 with freezing levels to 1900 metres, 1000 metres overnight.Friday: A mix of sun and cloud. Light variable winds. Alpine high temperatures around 0 with freezing levels to 2100 metres., 1500 metres overnight.Saturday: A mix of sun and cloud with cloud increasing over the day. Light southwest winds. Alpine high temperatures around 0 with freezing levels to 2100 metres, 1600 metres overnight.
Avalanche Summary
Reports from Tuesday showed skier traffic, ski cutting and explosives control yielding mainly small (size 1-1.5) storm slab releases, with slab depths of 10-20 cm. North to northeast aspects were the focal point and wide fracture propagations in these results were attributed to a poor bond between the new snow and the previous surface of crust.Looking forward, lingering wind slabs may remain reactive to human triggering and may become touchier with daytime warming. Meanwhile, an ample supply of new snow is in place to reinvigorate loose wet avalanche problems as sunshine and warming take hold each day.
Snowpack Summary
10 to 20 cm of new snow from Tuesday's storm has buried a surface of melt-freeze crust in most areas above 1500 metres. Below this elevation the new snow buried variably moist or crusty surfaces.Precipitation as rain continued to saturate the snowpack that is increasingly isothermal (slushy and cohesionless) and disappearing rapidly below about 1100 metres.The remainder of the snowpack is generally consolidated and strong. Exceptions may exist on north aspects above 2000 m, where a gradually strengthening layer of faceted grains buried 50 to 70 cm deep may still be preserved below an overlying slab of old and hard wind-affected snow.
Problems
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.