Archived

Avalanche Forecast

Apr 19th, 2014–Apr 20th, 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

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

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.

This bulletin was created using very limited field data. If you are out in the mountains, please send your observations to [email protected]

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Light precipitation is expected for the north coast on Sunday. Unsettled conditions are expected for Monday and Tuesday resulting in light scattered showers and a mix of sun and cloud. Overnight freezing levels will vary depending on local cloud cover.Sunday/Sun. Night: Precipitation 5-8mm, freezing level am: 900m pm: 12000m, ridgetop wind: moderate-strong S-SWMonday: A mix of sun and cloud, light scattered precipitation, freezing level am: 800m pm: 1200m, ridgetop wind: light SE-STuesday: A mix of sun and cloud, light scattered precipitation, freezing level am: 800m pm: 1100m, ridgetop wind: light SW-W

Avalanche Summary

Reports from Friday of sluffing from steep sun exposed terrain features and isolated slabs releasing from leeward features on ridgecrests.

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. In wind sheltered areas, the new storm snow has formed a storm slab which typically sits on a firm crust. 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 layer causing very large, destructive avalanches.

Avalanche Problems

Storm Slabs

Recent storm snow may have formed storm slabs in some areas and strong SW winds have formed stiffer wind slabs in leeward features.

Avoid freshly wind loaded features.>The new snow will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Loose Wet

Rain at lower elevations will saturate and destabilize the upper snowpack. Loose sluffing from steep terrain features is possible, especially from human-triggering.

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.

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