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Avalanche Forecast

Apr 7th, 2014–Apr 8th, 2014
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
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
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: Sea To Sky.

Check out the new Forecaster Blog to gain insight of how to manage cornices, and how warming influences the snowpack.

Confidence

Fair - Intensity of incoming weather systems is uncertain on Tuesday

Weather Forecast

Precipitation and strong SW winds will prevail as the cold front moves across the region Tuesday. Tuesday: Snow amounts up to 25 cm. Freezing levels 1900 m then dropping overnight to valley bottom. Ridgetop winds moderate from the SW. Wednesday/ Thursday: Mainly cloudy with possible sunny breaks in the afternoon and some flurries expected. Ridgetop winds light from the West. Freezing levels near 1200 m.

Avalanche Summary

Numerous size 1 wind slab, loose dry and loose wet avalanches were reported on Sunday. One size 2.5 slab avalanche was also reported and the failure plane was a buried crust, no other details noted. Cornices are sagging, with one failure a couple of days ago. With new snow and strong winds forecast for Tuesday, I suspect natural avalanche activity will be on the rise.

Snowpack Summary

Higher elevation areas have recently received up to 25 cm of new snow which sits on a variety of old snow surfaces including surface hoar, facets and melt freeze crusts. Isolated wind slabs have formed and a poor bond seem to exist, especially on slopes with a buried crust.Recent warm temperatures have helped to settle and strengthen the upper snowpack and tests are producing hard resistant planar shears on the late March crust. Below 1800 m a spring-like melt-freeze snowpack exists.Persistent weak layers exist lower in the snowpack. The mid-March surface hoar/ crust interface now down 80 -110 cm. The early-March crust/facet layer is down about 100-150 cm and the early February layer is now down close to 200 cm. These layers are largely dormant at this time; however, they should remain on your radar as we begin to transition into a warm-up with minimal overnight re-freeze.

Avalanche Problems

Storm Slabs

New snow and wind will form new slabs. A poor bond may exist, especially on slopes with a buried crust. Natural avalanche activity is possible for tomorrow and rider triggers are likely. Sagging cornices are a concern with warming.
Extra caution needed around cornices with current conditions.>Use extra caution and be conservative if you transition onto leeward slopes. Recent wind loading have created touchy wind slabs.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Deep Persistent Slabs

Three buried weak layers exist in the snowpack. Deep releases have become rare; however, the weak layers could be activated by cornice fall, a surface avalanche in motion, or intense loading from snow, and wind.
Be aware of thin areas that may propogate to deeper instabilites.>Be aware of the potential for large, deep avalanches due to the presence of buried facets and surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 3 - 7

Loose Wet

Rising freezing levels, warm temperatures and an insignificant overnight re-freeze will likely make the upper snowpack weak and cohesionless.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Watch for clues and avoid slopes if you start to see pinwheels, moist and/ or wet snow surfaces and natural avalanche activity.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 3