Avalanche Forecast

Issued: Dec 7th, 2013 8:21AM

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

swerner, Avalanche Canada

South Rockies.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

A weak disturbance may bring clouds and some flurries overnight into Sunday. The dominating arctic air mass will remain bringing very cold temperatures through the forecast period.Sunday: Cloudy in the morning with some snow accumulations up to 5 cm. Alpine temperatures are showing a high of -21. Light ridgetop winds from the North.Monday: Cloudy with some flurries near 4 cm. Alpine temperatures are showing a high of -20. Ridgetop winds strong from the SW. Tuesday: Cloudy with some sunny periods. Alpine temperatures are showing a balmy -14. Ridgetop winds are light from the West.

Avalanche Summary

No reports of avalanche activity.

Snowpack Summary

The South Rockies Field Team are back at it, Yeah! Snowpack depths at treeline seem to vary from 80 - 120 cm. Earlier this week the region received storm snow amounts of up to 70 cm. Strong ridgetop winds from the N-NE has redistributed snow onto S-SW aspects, creating reverse loaded slopes. Widespread wind effect is noticeable in the alpine and at treeline, but reports suggest they are stubborn to trigger.Below the recent storm snow down 30-40 cm a surface hoar/ facet/ crust interface. Snowpack testing showed easy results and some whumphing (failure of a weak layer below your feet). If you're seeing or feeling this, consider it a direct indicator of a buried weakness below.Near the base of the snowpack, I suspect you will find sugary facets, which will surely be growing with the extremely cold temperatures. The chance of triggering this layer is quite small under the current conditions, but if it was to happen, it would most likely be on a steep, convex slope with a thin snowpack.

Problems

Wind Slabs

Winds from the N-NE have developed wind slabs in the alpine and open areas in the treeline on SW-S aspects. These wind slabs may be easier to trigger in areas where a persistent weak layer exists.

Be careful with wind loaded pockets. Be aware of wide variation in snowpack depth>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Sugary facets at or near the base of the snowpack likely represent the most worrisome persistent layer at this time. The most likely place to trigger them is on steep, convex slopes with a thin snowpack.

Avoid shallow snowpack areas on steep, convex terrain where triggering is more likely.>Avalanche hazard may have improved, but be mindful that deep instabilities are still present.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Valid until: Dec 8th, 2013 2:00PM