Avalanche Forecast

Issued: Dec 27th, 2017 9:40AM

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

VIAC Dan Goodwin, VIAC

Summary

Confidence

Moderate - Uncertainty of incoming precipitation totals and freezing levels.

Travel/Terrain Advice

Be observant of storm snow totals and avoid recently wind loaded slopes and rollovers in the alpine and at treeline. Conditions will be more dangerous during the peak of the storm and will take some time to settle down. Keep an eye on rising freezing levels which will contribute to greater instability of the upper snow pack. Watch and listen for signs of instability such as shooting cracks or whumpfing. Test low consequence slopes and rolls and take note of the aspect, elevation and terrain characteristics.

Past Weather

Continued cold temperatures and light winds have dominated the story lately. Several weak disturbances have pushed through and delivered a small amount of snow accumulation to the Island mountains.

Avalanche Summary

No avalanches observed.

Snowpack Description

Surface - Highly variable surface conditions exist at all elevations. A recent dusting now covers the old surfaces which includes the dominant December inversion crust and is showing signs of bonding moderately well. Upper - Variable dependent on aspect and elevation. Some surface hoar has been observed in protected areas at treeline and below which is now buried by the recent snow. Mid - Well settled. Lower - Well settled.

Weather Forecast

A series of warm fronts will bring precipitation and a warming trend to Vancouver Island for the next few days. A weak system on Wednesday followed by a stronger warm front on Thursday will provide snow at higher elevations as the freezing levels rise. There will be a possibility of freezing rain in some elevation bands. Wed - 8-18 cm of snow with the southern region seeing higher totals. Winds 30-15 km/h southwest. Freezing levels of 300-1400 m. Higher freezing levels in the north. Thu - 14-23 cm of snow at higher elevations. Winds light southwest veering to light southeast. 14-32 km/h. Freezing levels of 440-1400 m. Fri - 3-10 cm of snow above 1000 m. Winds southwest 12-23 km/h. Variable in the afternoon. Freezing levels of 500-1250 m.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent new snow load and wind affect at upper elevations is highly variable. Both soft and hard wind slab can be found on leeward slopes in the alpine and exposed treeline areas. These problems are most likely to be encountered on southerly aspects. Natural avalanches are possible, especially if the incoming storm produces significant precipitation. These slabs will likely be reactive to light loads such as a skier or rider. Avalanches have the potential to be large in size, especially on large alpine features.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Storm Slabs

An icon showing Storm Slabs
Incoming precipitation and wind will likely create a new round of storm slab avalanches. These slabs are most likely to develop in the alpine and treeline elevations with the potential to be found on all aspects. Natural avalanches will be possible, especially at the height of the storm and may very likely be triggerable by a human. If the higher amounts of accumulation are received, these avalanches could be large in size.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 29th, 2017 6:00PM

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