Avalanche Forecast

Issued: Jan 16th, 2014 9:03AM

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

jlammers, Avalanche Canada

Cariboos.

Warm temperatures and sunny skies forecast for the next few days will have a significant weakening effect on the snowpack. If solar radiation is particularly strong the avalanche danger could rise to HIGH.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

A ridge of high pressure continues to dominate most of the province bringing mainly clear skies for the forecast period. Winds are expected to be light to moderate from the northwest, becoming westerly on Sunday. Alpine temperatures should hover between 0.0 and +5.0 on Friday and Saturday with some cooling expected for Sunday.

Avalanche Summary

A widespread natural avalanche cycle took place in recent days in response to heavy snowfall, rising temperatures and high winds. Numerous very large avalanches (size 3 and 4) have been reported. Wind slabs and shallow snowpack areas are areas of high concern. With forecast clear skies and warm temperatures, avalanche activity will likely include loose wet avalanches. Additionally, persistent slab avalanches will remain a very real possibility.

Snowpack Summary

Snowpack depths vary, but in general there is now 200 to 250cm of snow at tree line and as much as 300 cm in select places in the alpine. In some areas we're still dealing with a relatively thin snowpack thanks to a windy early season and strong winds scouring slopes during recent storms. About 100cm of storm snow fell over the past week and has been blown into stiff wind slabs in many areas. Below the recently formed storm slab you may find soft facetted snow and/or surface hoar buried around January 8th. This layer may coexist with a crust at lower elevations. Surface hoar layers buried in November and early December may still be found in the mid to lower snowpack, but are generally considered to be unlikely to trigger.A basal facet/crust combo ( weak sugary snow above and below a crust) near the ground is still a concern in some areas and was likely the reason so many large naturals were reported during and after this last storm cycle.

Problems

Persistent Slabs

Forecast warming will increase the likelihood of triggering a number of persistent weaknesses in the snowpack. Possible triggers include cornice fall. A persistent slab avalanche would be highly destructive in nature.

Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.>Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

3 - 7

Loose Wet

Forecast warming will likely produce loose wet avalanches in steep, sun-exposed terrain. A loose wet avalanche in motion may also "step down" triggering deep and destructive slab avalanches.

Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.>Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. >Sluffs may trigger deeper instabilities.>

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Wind Slabs

Although recently formed windslabs may be gaining some strength, they may still be triggered in steep, unsupported terrain. Watch for increased triggering with forecast warming.

Be cautious as you transition into wind affected terrain.>Be aware of the potential for wide propagations due to the presence of hard windslabs.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Jan 17th, 2014 2:00PM