Avalanche Forecast

Tuesday night: light flurries bringing trace amounts of new snow with moderate northwest winds. Low of -5 at 1700m.

Wednesday: A mix of sun and cloud with moderate to strong northwest winds. Freezing levels climbing to around 2000 m.

Thursday: Mainly sunny with moderate west winds. Freezing levels reaching near 2500 m with an inversion.

Friday: sunny with freezing levels around 1500m. Light north winds.

On Monday explosives triggered numerous cornices, with some subsequently triggering slabs on the slope below. Explosives also triggered a size 3 on the early December crust, this was a reloaded bed surface at 1900m that had previously avalanched.

On Sunday, a ski cut triggered a size 1.5 wind slab at 1950 m on a north aspect which was 15-25 cm thick and a skier accidently triggered a size 2 wind slab which failed down 30-60 cm on the mid-January crust. An explosive-triggered size 2.5 wind slab was also reported which failed on the mid-January crust down 30 cm and then stepped down to an older layer 100 cm deep in the snowpack. 

This MIN report summarizes the recent conditions well and describes natural and human-triggered slab avalanches size 1-2 as well as whumphing and shooting cracks. 

On Saturday, a natural cornice fall triggered a size 2 storm slab which failed down 30 cm and then stepped down to deeper layers in the snowpack. Several natural wind slabs size 1.5-2.5 were also reported in alpine terrain on NW-NE aspects. A small cornice failure was also reported which did not trigger a slab. 

A new melt-freeze crust is expected on solar aspects into the alpine and on all aspects at lower elevations. This crust will likely break down and become moist as the freezing level rises. Ongoing periods of strong wind from the southwest through northwest have formed reactive wind slabs and large cornices in exposed terrain at higher elevations. 

The January 30 interface is now typically down 20-40 cm and consists of a melt-freeze crust at lower elevations and on solar aspects extending into the alpine, spotty surface hoar in sheltered areas at and below treeline, and small facets in some areas. 

The widespread January 18 rain crust is now around 50-70 cm deep with weak faceted snow above. This layer appears to have woken up with the weekend warming and at least three avalanches likely involved this layer.

The early December crust/facet persistent weak layer is now 100-200 cm deep. This layer produced numerous large avalanches in January but is now considered dormant. See this forecaster blog on how to manage this layer as it may come into play again later this season. 

• Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
• Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
• Cornices become weak with daytime heating or solar exposure.
• Be careful as you transition into wind affected terrain.