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Archived

Avalanche Forecast

Mar 29th, 2015–Mar 30th, 2015
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
2: Moderate
The avalanche danger rating below treeline will be moderate
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
2: Moderate
The avalanche danger rating below treeline will be moderate
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
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: South Columbia.

Areas in the south may get some sun on Monday. Direct sun may spark a new cycle of avalanche activity.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Snow eases to light amounts on Monday, then the next pulse begins on Monday night, bringing around 5-10 cm snow through Tuesday with moderate to strong SW winds. Freezing levels are between 1800 m and 2200 m, dropping on Tuesday to around 1600 m and 1200 m by Wednesday.  

Avalanche Summary

On Saturday, a few naturally triggered persistent slabs, size 2-3, were observed. A widespread avalanche cycle ran on Thursday and Friday in response to wet and windy conditions. These were a mix of storm slab, loose wet avalanches and persistent slabs, up to size 3.

Snowpack Summary

Strong winds have shifted recent snow onto lee slopes at high elevations. Rain on Friday soaked the upper snowpack to at least treeline. Two persistent weak layers in the upper metre or so of the snowpack are the main story. The mid-March layer, around 60 cm down, is most reactive where it exists as a crust. Around 80-100 cm down, the mid-February facet/crust interface has also been reactive with large loads like smaller avalanches stepping down, cornice fall or explosives. Both layers are sensitive to triggering and propagate easily, causing very large avalanches.

Avalanche Problems

Storm Slabs

New snow and winds are likely to create touchy storm slabs, especially on features in the lee of the wind.
Avoid freshly wind loaded features.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Persistent Slabs

Large and destructive persistent slabs can be triggered by the weight of a person or sled. Stick to conservative terrain.
Choose conservative lines and only group up in safe terrain away from avalanche runouts.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 3 - 6