Avalanche Forecast

Issued: Apr 23rd, 2014 9:01AM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs, Loose Wet and Deep Persistent Slabs.

triley, Avalanche Canada

Northwest Coastal.

Due to a lack of field observations, we are starting to transition to bulletins without Danger Ratings. Check out this Blog Post for more information on spring ratings.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Thursday

Weather Forecast

Overnight and Thursday: Overnight freezing levels dropping down to 1000 metres and then rising up to 1500 metres during the day. Periods of broken skies overnight, and then mostly cloudy with light precipitation during the day. Winds light to moderate from the Southeast.Friday: Cloudy with light precipitation and not much overnight freezing. Winds light from the Southeast. Saturday: Winds becoming strong Southerly. Mostly cloudy with moderate precipitation falling as snow above 1000 metres.

Avalanche Summary

We received a report of a very large natural deep-slab avalanche east of Terrace on Monday. This avalanche occurred on a NW aspect at 1800m. The crown appears to be 1-2m deep meaning it likely released on the early-Feb weak layer. 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 forecaster@avalanche.ca

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 has been 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 likely still exists. 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, especially during warm sunny periods.

Problems

Wind Slabs

Recent wind slabs have become more stubborn to trigger, but may persist for a few more days.

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

Expected Size

1 - 3

Loose Wet

Snow may become moist or wet at lower elevations due to day time warming or from exposure to the sun.

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

Deeply buried persistent weak layers continue to be a concern for isolated hard to predict avalanches. Avalanches releasing on these deep layers may be more likely during periods of strong solar radiation, or when there is no overnight freeze.

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 - Possible

Expected Size

3 - 7

Valid until: Apr 24th, 2014 2:00PM