Avalanche Forecast

Issued: Dec 12th, 2011 8:52AM

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

mpeter, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Tuesday: Isolated flurries, with clouds lifting late in the day. Winds will be westerly up to 40km/h and temperatures should reach -8. Wednesday & Thursday: A weak ridge rebuilds over the region giving mostly clear conditions with light westerly winds and temperatures reaching -5 in the afternoons.

Avalanche Summary

Some sluffing of the new snow (up to size 1.0) has been reported, predominantly at treeline and below.

Snowpack Summary

10-20cm of new snow has fallen in the past couple of days. This overlies surface hoar (as large as 10mm in protected areas), surface facets, the odd old windslab and sun crusts (on steep south through west aspects). The new snow has fallen with limited winds effect. All of these newly buried surfaces are good sliding interfaces; all that's lacking is a large enough load. As more snow arrives and/or the wind picks up (as per the forecast) the avalanche danger will increase. Due to the slow, incremental increase in load (dribs and drabs of new snow and sporadic winds), this increase in danger is difficult to pinpoint and could be very site specific.In some locations there is a rain crust buried between 20-35cm. This crust extends as high as 2200m. Some faceting has been observed around the crust; definitely worth remembering this one.The early November surface hoar remains a layer of concern. Buried 100-150cm it is unlikely to trigger, but consequences of triggering would be a large (up to size 3.0) destructive avalanche.

Problems

Wind Slabs

Old windslabs still lurk in lee locations at ridgecrest in the alpine. Be aware of the new snow hiding these old slabs or forming into new soft slabs with the moderate westerly winds.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Dry

The new snow sluffs easily. Minimal hazard at this time, but something to keep in the back of your mind as the load increases.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

Probability of triggering has decreased. Where it still exists, this layer may be capable of producing highly destructive, full depth avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 13th, 2011 8:00AM