Avalanche Forecast

FRIDAY NIGHT - Mainly clear / moderate to strong southwest wind / alpine low temperature near 0 / freezing level 2500 m, dropping to 2000 m

SATURDAY - Mainly cloudy / moderate to strong southwest wind / alpine high temperature near -1 / freezing level 2000 m, dropping to 1500 m in the afternoon and to valley bottom overnight

SUNDAY - Mainly cloudy with isolated flurries, up to 5 cm / moderate to strong southwest wind / alpine high temperature near -5 / freezing level 1500 m, dropping to valley bottom overnight 

MONDAY - A mix of sun and cloud / light west wind / alpine high temperature near -5 / freezing level 1500 m, dropping to valley bottom overnight

There is a lot of uncertainty with regard to how quickly temperatures will drop on Saturday, and how the persistent weak layers will respond to the cooling trend. Though often less of a concern than rapid warming, cooling in the wake of warm temperatures can also trigger a spike in avalanche activity. 

On Friday, at the time of publishing, there were a few reports of human-triggered wet loose avalanches up to size 1.5, explosive triggered cornices up to size 1.5, and one explosive triggered size 2 persistent slab avalanche on a northeast aspect.

On Thursday, there were several reports of natural loose wet avalanches up to size 1.5 as well as natural and human-triggered wind and wet slab avalanches up to size 2. There were also a few reports of size 2.5 natural persistent slab avalanches in the nearby Waterton National Park region.

On Wednesday there were several reports of natural size 1 wet loose avalanches on solar aspects in the afternoon.

Warm temperatures and sunshine have made the snow surface moist in most areas. Dry snow may still be found on north aspects. The moist snow will change into a crust when temperatures finally dip back below zero. Wind slabs are likely still present on northerly aspects in the alpine and at treeline.

Up to 50 cm of snow sits above a variety of old interfaces that formed in mid-February. There is 60-100 cm sitting on a persistent weak layer that was buried in late January. These interfaces are mostly made up of sugary facets, hard wind pressed snow, surface hoar in wind-sheltered locations, and sun crust on steep solar aspects. Recent test results indicate that the late January persistent weak layer is potentially still quite reactive.

• Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
• Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
• A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
• The trees are not the safe-haven they normally are at this time. Terrain at treeline is primed for human triggered avalanches.
• Back off if you encounter whumpfing, hollow sounds, or shooting cracks.