Archived

Avalanche Forecast

Apr 14th, 2014–Apr 15th, 2014

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

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

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Northwest Coastal.

This bulletin has been produced using very limited field data. If you've been out in the mountains we'd love to hear about what you've seen. Observations can be sent to [email protected]

Confidence

Fair - Due to the number of field observations

Weather Forecast

Tuesday: Light to locally moderate snowfall / Light to moderate southwest winds / Freezing level at 1000mWednesday: Mix of sun and cloud / Light to moderate southwest winds / Freezing level at 1250mThursday: Moderate to locally heavy snowfall / Moderate to strong southwest winds / Freezing level at 1250m

Avalanche Summary

Although recent observations have been extremely limited, a solar induced natural avalanche cycle to size 3 occurred over the weekend. Loose wet and slab avalanches were noted in this cycle with most activity occurring in steep terrain. Of note, a size 4 deep persistent avalanche occurred in the far north of the region. It released initially within the recent storm snow and stepped down to basal facets. Solar induced activity is expected to taper-off with a possible shift to wind slab activity with forecast weather.

Snowpack Summary

Last week's storm brought 90+ cm or more to coastal regions forming thick storm slabs on leeward features. Warmer temperatures have helped to settle the recent snow, although the storm snow may continue to be touchy where it overlies surface hoar, crusts and/or facets buried at the beginning of April. Sun exposed slopes and lower elevation terrain has seen a daily melt-freeze cycle, and many slopes below treeline are likely isothermal. Large cornices have formed and loom over slopes below.The early February crust/facet layer is down 150 - 240 cm. Triggering this destructive layer will become unlikely with forecast cooling.

Avalanche Problems

Storm Slabs

Forecast snowfall will add to existing deep storm slabs which formed last week. Although these storms slabs have become less likely to trigger, large avalanches may still result where they overlie weak layers buried at the beginning of April.

Be cautious as you transition into wind affected terrain.>Avoid unsupported slopes.>Make observations and assess conditions continually as you travel.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4

Deep Persistent Slabs

Deep and destructive persistent slab avalanches will become less likely with the forecast cooling trend. Possible triggers include cornice fall, warming and intense solar radiation.

There is potential for large, deep avalanches due to the presence of buried facets and surface hoar.>Conditions have improved, but be mindful that deep instabilities are still present.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 3 - 7