Avalanche Forecast

Moderate - We have a good understanding of the snowpack structure and confidence in the weather forecast Uncertainty is due to the fact that deep persistent slabs are particularly difficult to forecast.

Wednesday Night: Mostly cloudy, localized clearing. No new snow expected. Light variable wind, periods of strong northwest at higher elevations, decreasing through the night. Freezing levels drop to valley bottom. Alpine low around -7 C.

Thursday: Partly cloudy in the morning, clearing through the day. No new snow expected. Light southwest wind trending to strong northwest at higher elevations. Freezing level at valley bottom overnight, rising to 750 m by the afternoon. Alpine high around -5 C.

Friday: Partly cloudy in the morning, sunny by the afternoon. No new snow expected. Moderate southwest wind trending to extreme west at higher elevations. Freezing level at valley bottom overnight, rising to 1000 m by the afternoon. Possible temperature inversion bringing alpine highs to around -2 C.

Saturday: Mostly sunny. No new snow expected. Moderate southwest wind trending to extreme west at higher elevations. Freezing level at valley bottom overnight, rising to 900 m by the afternoon. Temperature inversion breaking down.

On Tuesday, neighbouring Waterton National Park reported a few small to large natural windslab avalanches from steep, alpine features, and a couple of small, rider triggered windslab avalanches on reverse loaded, steep rolls.

No new avalanches were reported on Wednesday before 4 pm.

Surface hoar up to 15 mm has been reported in areas around Fernie. Mountain Information Network post also reports surface hoar in the Corbin aand Morrisey areas. See here and here for more details. Patchy sun crust may exist on steep, solar aspects.

The upper snowpack consists of windslabs 20-60 cm deep in exposed terrain, and 15-20 cm of settling storm snow from last week.

Around 2200 m and below, these windslabs overlie a crust buried on January 18th, which caps a dense 15 to 30 cm of settled snow. On some windward slopes, the wind has scoured the surface back down to this crust. The crust varies with aspect and elevation from thin (2 cm thick) in the alpine to (4 cm) thick below treeline. 

The midpack is strong and well consolidated above the early December crust/ facet interface.  

The most notable layer of concern in the snowpack is a widespread crust that was formed in early December and is now down 100-250 cm. Daytime warming, solar radiation, smaller avalanches, and cornice fall could all play a role in triggering low probability, high consequence deep persistent slab avalanches. 

• If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
• Carefully evaluate bigger terrain features on an individual basis before committing to them.
• Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
• Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.