Avalanche Forecast

Issued: Dec 28th, 2017 4:54PM

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.

mbender, Avalanche Canada

Cariboos.

There will continue to be a slow accumulation of low density new snow in the coming days.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

FRIDAY: Isolated flurries / Light to moderate east wind / Alpine temperature -11 SATURDAY: Flurries, accumulation 5cmÂ / Light south wind / Alpine temperature -12 SUNDAY: Mix of sun and cloud / Light southwest wind / Alpine temperature -11

Avalanche Summary

Recent reports are limited to both natural and human triggered loose dry avalanches in steep terrain to size 1 in areas that have not been affected by wind. Please submit your observations to the Mountain Information Network (MIN).

Snowpack Summary

Up to 5cm of low density new snow has buried a recently formed layer of weak feathery surface hoar and/or sugary facets. A layer buried mid-December that consists of surface hoar, sun crust and/or sugary facets is now down approximately 20-40cm. The bond at this old snow interface is of critical importance in areas where the overlying snow has consolidated into a slab. The most concerning areas are those that saw pronounced surface hoar development before the storm, such as sheltered areas at and below treeline, sheltered northerly aspects in the alpine, or anywhere the surface hoar formed on top of a sun crust. Recent snowpack tests show wide ranging reactivity on this weak layer. A crust which was formed by rain in late November is another major feature in the snowpack and is down approximately 70-100cm at tree line elevations. This interface has shown some signs of reactivity limited to steep, variably loaded alpine features in the adjacent North Columbia region.

Problems

Wind Slabs

Recent shifting winds have been redistributing loose snow into wind slabs on a variety of aspects.

Be aware of recent variable wind loading patterns.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

A weak layer of surface hoar buried 20-40 cm deep has potential to be reactive where the overlying snow has settled into a cohesive slab.

Buried surface hoar is more likely to be preserved in sheltered openings at and below tree line.Watch for signs of slab formation at lower elevations, such as whumphing or shooting cracks.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 29th, 2017 2:00PM