Archived

Avalanche Forecast

Apr 21st, 2014–Apr 22nd, 2014

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

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

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: Northwest Coastal.

Avalanche danger can rise quickly with afternoon warming and solar radiation. Be aware of changing conditions and overhead hazards.For more insight into spring danger ratings, check out this blog post.

Confidence

Poor - Due to the number of field observations

Weather Forecast

Unsettled conditions are expected for Tuesday. Wednesday and most of Thursday look to be mainly dry and sunny but localized convective flurries are possible. A Pacific frontal system is expected to reach the north coast Thursday night. Tuesday: Cloudy with sunny breaks, scattered precipitation, freezing level am: 700m pm: 1000m, ridgetop wind: light variableWednesday: Mostly sunny, freezing level am: 700m pm: 1400m, ridgetop wind: light SE-SThursday: A mix of sun and cloud, freezing level am: 1400m pm: 1700m, ridgetop wind: light SE

Avalanche Summary

No new avalanches reported.Â We are no longer receiving professional daily reports for the region so public observations are really appreciated right now. If you are out in the mountains, send your observations to [email protected]

Snowpack Summary

Highly variable spring conditions are being reported in the region. At lower below-treeline elevations the snowpack is typically wet and isothermal. It has not been refreezing overnight and is melting quickly. Between roughly 1000 and 1500m, the snowpack is undergoing daily melt-freeze cycles. The same conditions can be expected on sun-exposed slopes all the way to mountain-top. On higher elevation north-facing slopes, dry snow can be found. Recent strong S through W winds have scoured windward slopes and created wind slabs in leeward slopes. The early February crust/facet layer is typically down 1.5 to 2.5m. A smaller avalanche or a cornice fall may still have the potential to step down to this layer causing very large, destructive avalanches.

Avalanche Problems

Wind Slabs

Recent strong SW winds have formed wind slabs in leeward features.

Be cautious as you transition into wind affected terrain.>Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Loose Wet

Loose wet activity can be expected from steep features during periods of solar warming or rain. Isolated wet slabs may be possible under the same conditions where the recent storm snow is poorly bonded to the underlying crust.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 2

Deep Persistent Slabs

A deeply buried persistent weak layer still has the potential to produce very large avalanches and could be triggered by heavy triggers such as cornice falls or smaller avalanches stepping-down.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 3 - 7