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Avalanche Forecast

Mar 12th, 2017–Mar 13th, 2017
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
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
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: South Columbia.

Snow, wind and warming are a recipe for elevated danger. Storm and wind slabs will be touchy at treeline and above. Avoid overhead hazard: Conservative terrain use is essential this week!

Confidence

Low - Intensity of incoming weather systems is uncertain

Weather Forecast

We'll have moderate snowfall amounts through to Monday afternoon, and then it starts to warm up.MONDAY: Cloudy with another 15-20cm by late afternoon accompanied by moderate to strong SW winds and freezing levels rising as high as 1500m.TUESDAY: Scattered flurries (3-5cm) with moderate southerly winds. Freezing levels remain near 1600m.WEDNESDAY: Cloudy with another 10-20cm of fresh snow throughout the day accompanied by moderate SW winds. Alpine temperatures hovering around -2 C.

Avalanche Summary

On Sunday we had reports of a widespread natural avalanche cycle up to Size 3 on all aspects and elevations at treeline and in the alpine.

Snowpack Summary

Around 40-60cm of fresh snow has fallen over the past three days (with light to moderate southerly winds) and has added to the 50-100cm of settled storm snow from the past week. Touchy storm slabs can be found at all elevations with weaknesses within and under this recent snow.All this new snow is bonding slowly to faceted snow as well as isolated small surface hoar in sheltered areas and a thin sun crust on steep southerly aspects.The persistent weakness buried mid-February is now down 80-140 cm, and is composed of a thick rain crust as high as about 1800 m, sun crusts on steep southerly aspects, and spotty surface hoar on shaded aspects. Recent reports show the bond to this interface becoming more variable.The mid and lower snowpack are well settled and stable in deeper snowpack areas, but may be weak and faceted in shallow areas.

Avalanche Problems

Storm Slabs

Weaknesses within the recent storm snow are susceptible to human triggering. These storm slabs are particularly deep and touchy on slopes loaded by southerly winds and have the potential to step down to deeper persistent weaknesses.
The new snow will require several days to settle and stabilize.Be alert to conditions that change with elevation.Be increasingly cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3

Persistent Slabs

Various persistent weaknesses strewn throughout the snowpack create the potential for large step-down avalanches. Warming is expected to increase the likelihood of these large avalanches, especially with cornice-fall triggers.
Use conservative route selection, choose moderate angled and supported terrain with low consequence.Be aware of the potential for wide propagations.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 2 - 4