Avalog Join
Archived

Avalanche Forecast

Dec 12th, 2012–Dec 13th, 2012
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Cariboos.

Confidence

Fair - Due to limited field observations

Weather Forecast

A weak system will cross the region during Thursday and bring light precipitations and moderate to strong winds from the South West. Temperatures will stay cool for the entire period. Friday should see some sunny periods with lighter winds from the North West. Later Saturday, another upper trough is expected to spread moderate snow accumulations over the region with moderate winds from the South.

Avalanche Summary

Several natural slab avalanches up to size 2 have been reported on various aspects in the storm snow. A few skier triggered loose dry avalanches have also been reported on steep terrain.

Snowpack Summary

30 cm of fresh snow has been transported by West and South West winds in the alpine and treeline  creating the windslab problem on lee slopes. It has been reported that these windslabs are reactive under the weight of a skier. In sheltered areas, this new snow could also be burrying older and deeper windslabs in the alpine. Sluffing is still an issue on steep features protected from the wind below treeline. Below treeline, also watch for early season obstacle, such as stumps and creeks. The deep persistent instabilities (surface hoar and early November crust) located in the middle and near the bottom of the snowpack are still a concern in this region, however, we haven't had report of their sensitivity or reactiveness. Digging down and making your own observations will be critical to safe slope selection. Any observations from the field are welcome at forecaster@avalanche.ca.

Avalanche Problems

Wind Slabs

Expect buried windslabs in sheltered area and newly formed windslabs in exposed lee slopes and cross-loaded gullies below ridge crests.
Use ridges or ribs to avoid pockets of wind loaded snow.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 5

Deep Persistent Slabs

Be extra careful in areas where ground roughness is not present to act as anchorage. Smooth ground cover areas include firn on glaciers, grassy slopes and rock slabs.
Common trigger points for this type of layer is shallow-rocky snowpack areas and areas with smooth ground cover.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 3 - 7