South Rockies

We're entering a period of warming that may expose the weakness buried at the base of our snowpack. The possibility for large natural slab avalanches will increase with warmth and sun exposure.

High -

Thursday night: Cloudy with clear periods and isolated flurries with a trace of new snow. Light southwest winds increasing to strong northwest in the alpine.Friday: A mix of sun and cloud. Moderate northwest winds increasing to strong in the alpine. Winds increasing overnight. Alpine high temperatures around -5.Saturday: Mainly sunny. Strong west winds reaching extreme in the alpine and increasing overnight. Alpine high temperatures around 0 to +1 as freezing levels jump to a possible 2500 metres.Sunday: A mix of sun and cloud with isolated flurries and a trace of new snow. Extreme northwest winds decreasing to moderate over the day. Alpine temperatures dropping from around 0 to -4 over the day as freezing levels decline from 2000 to 1000 metres.

Wednesday's avalanche observations were limited to small (size 1), thin slabs released with ski cutting. Looking forward into a period of forecast warming, our primary concern is the potential for a relapse into conditions observed a couple of weeks ago when warm temperatures stressed the deeper layers in the snowpack and produced several large (size 2) natural deep persistent slab avalanches.

Strong winds have redistributed snow into thin winds slab in alpine lees and scoured windward areas. In more sheltered alpine terrain and between 1600-2000 m, 5-15 cm of recent snow overlies a layer of weak surface hoar and crusts (on solar aspects). Large variability in snow depths still exists in the region, ranging from almost no snow to nearly 200 cm in some areas. For average snowpack areas, expect to find weak and sugary faceted snow around 50 to 100 cm deep, which extend to the ground. This weak bottom half of the snowpack has been the culprit for large avalanches in the region over the past few weeks.