Avalanche Forecast

A ridge of high pressure builds on Saturday bringing dry and sunny conditions with mild temperatures. 

Friday Night: Snowfall up to 5 cm, light to moderate SW wind, treeline temperature around -8 °C. 

Saturday: A mix of sun and cloud, light to moderate NW wind, freezing level reaching as high as 1500 m. 

Sunday: Mainly sunny, light to moderate W wind, freezing level may reach over 2000 m in the afternoon with an inversion. 

Monday: A mix of sun and cloud, moderate W wind, freezing level over 2000 m in the morning with an inversion, breaking down through the day. 

On Thursday, a skier remotely triggered a size 1 storm slab from 30 m away in the southwest of the region which failed on the Jan 30 surface hoar down 40 cm. 

On Wednesday, human-triggered storm and wind slabs to size 1 were reported. In the southwest of the region, remote triggers were also reported, producing small slab avalanches failing on the buried surface hoar layer. 

Natural wind slabs had been observed earlier in the week, mainly during peak loading from strong westerly winds. Loose dry avalanches have also been reported from steep terrain features.

Prior to Friday's storm, 20-40 cm of snow from last Sunday buried the January 30 interface which consists of a melt freeze crust at lower elevations and on solar aspects extending into the alpine and widespread surface hoar in sheltered areas at and below treeline which is typically up to around 15 mm in size and very weak in some places. Prior to Friday's storm, the older storm snow had not formed a slab in most places except for where it was wind loaded. With warming and sun this weekend, rapid settlement is possible and this may result in the formation of a more widespread reactive slab over the weak surface hoar and crust. Ongoing wind over the past week has formed reactive wind slabs in exposed terrain at higher elevations and new wind slabs may build during Friday's storm.

Several surface hoar layers are now buried in the upper snowpack 30-60 cm deep. While these have been dormant recently, they will also get tested this weekend with warming and sun. 

The early December crust/facet layer of concern sits around 80 cm deep in the eastern Purcells and shallow terrain, and up to 150 cm in the west. This layer produced numerous large avalanches in January but is now considered dormant. We continue to track this layer of concern and expect it will wake up again with sustained warming or a large storm event. This recent forecaster blog goes into more details on the layer and how to manage it. 

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
• Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
• The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.