Avalanche Forecast

Issued: Jan 31st, 2018 9:00AM

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

VIAC Bill Phipps, VIAC

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Vancouver Island.

Summary

Confidence

High - Weather models in agreement and good data for east and north. (limited obs for the west/Strathcona).

Travel & Terrain Advice

Avoid exposure to wind loaded slopes in the alpine and treeline on NE-NW aspects. Wind slabs will have a poor bond to the near surface crust. As the rain begins to fall avoid exposure to terrain traps such as cliffs, tree bands and depressions like streams. Also avoid travel in gullies that will funnel the potential wet slides. The crust from Sunday’s rain event has variable support to both skis and foot traffic and is very difficult to travel on. Frozen debris from wet slides and tree bombs also presents a navigation challenge. Move slow and carefully as these hazards now lurk under newly fallen fresh snow.

Avalanche Summary

No new avalanche activity reported during the past two days. Clear skies have allowed observations of the widespread wet loose and wet slab activity during Sunday’s rain event. As expected there are numerous paths that ran up to size 1 and a few up to size 2.

Snowpack Summary

A dusting of new snow over a nasty crust. A few isolated wind slabs near ridge line and on cross loaded features.

Snowpack Details

Surface: Variable support rain crust, buried under light amounts of new snow. Upper: Moist snow from Sunday's rain event. Mid: Preserved dry snow with a few smooth failures in tests. Lower: Well settled.

Past Weather

Cold temps have created a widespread rain crust that is now buried under light to moderate amounts of new snow. Moderate SW winds have created isolated wind slabs that have a poor bond to the crust below.

Weather Forecast

Moderate new snow giving way to our next rain event. Wednesday: 5-10 cm of new snow, temps -3 to -6, winds light to moderate SW-SE, freezing level 0-800 m. Thursday: 5-10 cm of new snow leading to 2-5 mm of rain, temps -5 rising to +3, winds light SW rising to moderate SE, freezing level 700 rising to 1150-1900 m. Friday: 2-10 mm of rain, temps +3 dropping to 0, winds light to strong from the SW, freezing level 2600 dropping to 1500 m.

Problems

Wind Slabs

An icon showing Wind Slabs
Moderate new snowfall with moderate SW-SE winds will form wind slabs on NE-NW aspects and cross loaded features in the alpine and treeline. With a poor bond to the rain crust from Sunday, these slabs will likely trigger with human activity but are unlikely to trigger naturally up to size 1-1.5.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 1.5

Loose Wet

An icon showing Loose Wet
Rain forecast for late Thursday into Friday will potentially lead to widespread loose wet avalanche activity on all aspects and elevations. These slides will very likely trigger naturally and will almost certainly trigger with human loads. We can expect many widespread slides up to size 1 and potentially a few up size 2.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely - Certain

Expected Size

1 - 2

Wet Slabs

An icon showing Wet Slabs
Wind slabs formed on NE-NW aspects in the alpine and treeline will convert to wet slabs with the forecast rain. These slabs could possibly trigger naturally and are very likely to move with human triggers up to size 2.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: Feb 2nd, 2018 9:00AM

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