Archived

Avalanche Forecast

Mar 6th, 2014–Mar 7th, 2014

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

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

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Regions: Glacier.

Continued loading from snowfall and warm temp's have created a dangerous surface slab. Might be wise to visit your local ski hill today!

Weather Forecast

Another storm pulse will head through Rogers Pass today, bringing 10-20cm of snow, with freezing levels continuing to rise to 1600m. Winds are expected to be moderate from the SW, gusting strong. Friday will see a slight break in the snowfall, but more is forecasted to arrive Saturday and Sunday, with freezing levels shooting up to 2000m.

Snowpack Summary

30-50cm of heavy snow over light snow has created a touchy soft slab. This lies on top of suncrusts on solar aspects, and windslab on N and E aspects. The new slab is failing with easy to moderate results within the new snow, as well as at the old interface. The Jan 28/Feb 10 PWL is down 1.2-1.5m under a cohesive slab.

Avalanche Summary

Artillery control yesterday and this morning has produced excellent results, with avalanches to size 3.5 running fast and to the end of their run-outs. Few observations were made in the backcountry, but given the natural activity in the highway corridor, it is safe to say there is a natural avalanche cycle on-going.

Confidence

Avalanche Problems

Storm Slabs

A touchy slab lurks on the slopes, and were easily triggered by field teams and artillery control at all elevations. As it becomes more cohesive from snow-load and warming temp's, we expect this slab to propagate easily.

Minimize exposure during periods of heavy loading from new snow, wind.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 3

Loose Dry

Plenty of new, loose snow is available for sluffing in steep terrain. Practice good terrain and group management, and avoid getting pile-driven into terrain traps by the snow you just skied.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Be aware of party members below you that may be exposed to your sluffs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

The facet/crust "sandwich" is buried 120-150cm below the surface now. It is still producing hard, sudden results in tests, indicating that it can will propagate if a large enough trigger hits it. Avalanches digging into this layer will be large!

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 2 - 4