Avalanche Forecast

Issued: Dec 18th, 2019 4:00PM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada shorton, Avalanche Canada

Email

Dangerous avalanche conditions continue as storm snow continues to accumulate and stress buried weak layers.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

WEDNESDAY NIGHT: Snow, accumulations of 10-25 cm, 50 km/h wind from the south, alpine temperatures drop to -8 C.

THURSDAY: Scattered flurries with another 5 cm of snow, 50 km/h wind from the south, alpine high temperatures around -4 C.

FRIDAY: 15-25 cm of snow, 50-70 km/h wind from the south, alpine high temperature -4 C.

SATURDAY: 5-10 cm of snow in by the morning then clearing in the afternoon, 30 km/h wind from the south, alpine high temperatures around -4 C.

Avalanche Summary

Heavy snowfall likely resulted in a cycle of natural avalanches on Tuesday and Wednesday, leaving storm slabs very reactive to human triggering. Observations have been limited the past few days due to poor visibility.

Similar activity is expected on Thursday with more snow expected overnight and strong wind throughout the day.

Snowpack Summary

A continuous pulse of storms has delivered anywhere from 20-50 cm of snow to the Cariboos over the past few days. 40-80 cm of recent snow now sits above a widespread layer of large, feathery surface hoar crystals. New snow is expected to continue to accumulate and consolidate above this layer over the next few days, maintaining a high likelihood of human-triggering.

A weak layer formed in late November is now buried around 1 m plus below the surface. This is the layer of concern relating to the persistent slab avalanche problem. The weak layer may present as surface hoar, a crust, facets or a combination, depending on elevation and aspect. Below this, a variety of crusts from late October are buried deeper in the snowpack.

Problems

Storm Slabs

An icon showing Storm Slabs

Continuous snowfall and strong wind has formed touchy storm slabs. The conditions are primed for human triggered avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

A couple of weak layers formed in late November and early December are now sitting about 1 m below the surface.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Dec 19th, 2019 4:00PM