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 -20 C.

SATURDAY: Sunny with a few clouds, light to moderate east wind, alpine temperatures around -18 C.

SUNDAY: Mix of sun and cloud, light south wind, alpine temperatures around -15 C.

MONDAY: Sunny with a few clouds, light variable wind, alpine temperatures around -12 C. 

Small to large (size 1-3) natural and human-triggered wind slab avalanches have been reported consistently throughout the week in the alpine, some of which were triggered by solar radiation or cornice falls. This MIN report from neighboring Glacier National Park on Thursday offers a helpful visual of this avalanche activity. Operators have also reported numerous recent dry loose avalanches (size 1-1.5).

On Wednesday, there were two notable large (size 2.5-3) human-triggered avalanches reported just outside of Glacier National Park on south and west facing alpine slopes (MIN report). These persistent slab avalanches likely failed on a facet and crust layer buried Jan 24th.

Over the past week the persistent slab problem has produced fewer avalanches than in the first week of February, but is still showing signs of instability in snowpack tests and warrants careful assessment.

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. 60-100 cm of snow from February is settling over a layer of surface hoar. Reactivity on this layer has primarily been observed at treeline and in "treeline-like" features that are below treeline, however facets above a sun crust may be found on steep south facing features. Snowpack tests results continue to show the potential for propagation on this layer, like this MIN report from Clemina on Monday and this MIN report from the Gorge on Tuesday. The mid/lower snowpack is generally well settled and strong.

• Recent wind has varied in direction so watch for wind slabs on all aspects.
• Approach lee and cross-loaded slopes with caution.
• Cornice failure may trigger large avalanches.
• Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.