Avalanche Forecast

Moderate - Recent weather patterns have resulted in a high degree of snowpack variability within the region. Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

THURSDAY NIGHT - Mainly cloudy with flurries, 5 cm / moderate to strong west wind / alpine low temperature near -10 

FRIDAY - Mainly cloudy with a few flurries / moderate northwest wind / alpine high temperature near -9

SATURDAY - A mix of sun and cloud / light to moderate northwest wind / alpine high temperature near -11

SUNDAY - A mix of sun and cloud / moderate to strong west wind / alpine high temperature near -7 / freezing level 1500 m

On Wednesday, there were a few reports of natural and explosive triggered size 2 storm and wind slab avalanches, as well as a few natural and explosive triggered cornices up to size 3. There were also a few notable remotely triggered avalanches reported in the north of the region that are suspected to have failed on the recently buried facets. The MIN report can be viewed here.

Reports of storm slab avalanches from Monday and Tuesday near Golden include size 2-2.5 naturals, some of which were cornice triggered; size 2 explosive results; and human-triggered size 1's.

Near Invermere, natural, explosive and human-triggered wind slab avalanches were mainly in the 1-1.5 size range on Monday and Tuesday. A natural size 2 wind slab on a northeast aspect is suspected to have stepped down to deeper persistent layers.

Earlier in February, there were a few reports of large avalanches (size 2.5-3) on southeast aspects in the alpine, likely releasing on a layer of facets on a crust (see a photo here), and a large human-triggered avalanche (size 2.5) on surface hoar near Quartz Creek.

Recent snowfall amounts have varied throughout the region from less than 10 cm in the east to 40-50 cm along the western part of the region, and near Golden. At upper elevations, this snow has been blown into slabs in lee terrain features. 

The recent snow sits on weak, faceted snow that formed during the last cold snap. We expect this interface to stick around for a while, and it may be tricky to manage due to the highly variable depth of the layer throughout the region. This MIN from one of the highest snowfall areas gives a great account of this variability, even on a small scale.

A weak layer that formed in late January is now 30-90 cm deep. In the northern Purcells, this layer has been reported as a surface hoar layer at treeline and below, but a combination of facets or crusts could exist at all elevations. A couple of recent wind slab avalanches near Golden and Invermere have been suspected to have stepped down to this layer in the alpine.

The northern Purcells also have an older surface hoar layer that can still be found 60-120 cm deep at treeline. Additional weak layers may exist near the bottom of the snowpack and steep rocky areas with a shallow or thin to thick snowpack should be considered suspect trigger points.

• Be especially cautious as you transition into wind affected terrain.
• Recent wind has varied in direction so watch for wind slabs on all aspects.
• Choose slopes that are well supported and have limited consequence.
• Be aware of the potential for large avalanches due to the presence of a persistent slab.
• Avoid shallow, rocky areas where the snowpack transitions from thick to thin.