Avalanche Forecast

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

FRIDAY NIGHT: Clear, light to moderate east wind, alpine temperatures around -17 C.

SATURDAY: Sunny with a few clouds, light to moderate east wind, alpine temperatures around -16 C.

SUNDAY: Mix of sun and cloud, light south wind, alpine temperatures around -16 C.

MONDAY: Mix of sun and cloud, light variable wind, alpine temperatures around -12 C. 

Reports of avalanches on Friday consisted of of small to large (size 1-2) wind slab avalanches near treeline and above as a result of moderate east winds. This MIN report from neighboring Glacier National Park on Thursday offers a helpful visual of this avalanche activity. Operators continue to report numerous small dry loose avalanches. 

There has been recent notable avalanche activity in and around Glacier National Park. On Friday, observers reported a large (size 2.5) natural avalanche on a southeast aspect in the alpine, breaking on a facet crust layer buried Jan 24th. Similarly, on Wednesday, there were two large (size 2.5-3) human-triggered avalanches reported just outside of Glacier National Park on south and west facing alpine slopes (MIN report), also failing on the persistent weak layer.  

Last weekend and earlier this week, there were numerous reports of persistent slab avalanches across the region, including some in lower elevation cutblocks in the southern Selkirks (here and here), a wind slab on a southeast aspect that stepped down to a deeper layer to produce a size 3 avalanche on London Ridge, and a size 1.5 skier triggered slab near Revelstoke (MIN report).

On Thursday, winds picked up out of the east/northeast with enough gusto to move snow around, giving new life to wind slab problems in the region. Watch for wind slabs in uncharacteristic places at upper elevations as easterly winds continue.

While wind may be forming slabs in lee features, the upper snowpack is becoming soft and faceted with the cold temperatures. 60-120 cm of snow from February is settling over a weak layer of surface hoar that has shown reactivity at treeline or in "treeline-like" features below treeline. On steep south facing terrain this layer may consist of facets on a sun crust. This persistent weak layer has potential to surprise backcountry users with how wide the fracture can travel across slopes. This layer will be slow to gain strength and requires careful terrain selection. The mid/lower snowpack is generally strong and settled in most areas.

• Recent wind has varied in direction so watch for wind slabs on all aspects.
• Approach lee and cross-loaded slopes with caution.
• Be aware of the potential for large avalanches due to the presence of a persistent slab.
• Extra caution is needed around cornices under the current conditions.