Avalanche Forecast

Issued: Jan 15th, 2014 8:49AM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.

triley, Avalanche Canada

Kootenay Boundary.

Forecast strong solar radiation and very warm alpine temperatures are driving the danger ratings up for the next few days. Stay tuned for more news on the warm-up.

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Overnight and Thursday: Very strong Northwest winds at higher elevations becoming moderate by late morning. Below freezing temperatures are expected overnight in the alpine. Freezing levels climbing to about 2700 metres during the day. Mostly clear with strong solar radiation.Friday: Very warm temperatures are forecast, plus 5 degrees at ridge tops and above freezing at the highest alpine peaks. Light winds and mostly clear skies, with strong solar radiation.Saturday: Continued very warm clear and sunny with light winds.

Avalanche Summary

Some loose wet avalanches reported from steep solar aspects to size 1.0

Snowpack Summary

The North of the region received more storm snow over the past week than the rest of the region. The storm slab in the North is close to a metre thick and appears to be more touchy than in most of the rest of the region. The Rossland range has a shallower snowpack and weak basal facets continue to be a concern where wind slabs and storm slabs have added load above the weak layers. The forecast very warm alpine temperatures may result in a period of fairly rapid warming of wind and storm slabs above loose weak layers. Periods of strong solar radiation may cause moist or wet loose snow avalanches and/or cornice falls which may result in large additional loads above deeply buried weak layers.

Problems

Wind Slabs

Recent storm snow has been transported into wind slabs at higher elevations. Some areas may have wind slabs that are about one metre thick. Very warm alpine temperatures may result in loose wet avalanches on southerly aspects.

Be aware of the potential for wide propagations due to the presence of hard windslabs.>Be cautious as you transition into wind affected terrain.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

Recent storm snow may not be bonding to the surface hoar and melt-freeze crusts that developed before the storm. Storm slabs are more likely in areas sheltered from the recent strong winds

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar, facet/crust and depth hoar.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Deep Persistent Slabs

This problem is more likely in areas that had a shallow snowpack during the cold arctic outbreak. Loose wet avalanches or cornice falls may trigger deeply buried weak layers resulting in large destructive avalanches.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Jan 16th, 2014 2:00PM