Avalanche Forecast

Issued: Dec 25th, 2013 7:57AM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Storm Slabs, Persistent Slabs and Deep Persistent Slabs.

esharp, Avalanche Canada

Cariboos.

Expect avalanche danger to increase throughout the day. Danger may be lower in areas that receive less snowfall than forecast.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Synopsis: A series of frontal systems pushing across Northern BC will bring moderate to heavy precipitation to the Caribous Tonight through Friday. Saturday will see a return to relatively cool and dry conditions in the wake of the storm.Tonight and Thursday. Snow amounts: 20-40 cm. Ridge winds: Strong westerly. Freezing levels: Rising to 1500m.Friday. Snow amounts: Up to 10 cm. Ridge winds: Strong westerly. Freezing levels: 1200m.Saturday: Flurries. Ridge winds: light northwesterly. Alpine temps: -10.

Avalanche Summary

We've received recent reports of the basal weaknesses causing large natural avalanche to ground on N to NE aspects.Reports of avalanches on the early December surface hoar from the Monashees where the snow amounts of the last storm were greater suggest that we may see a similar cycle develop in the Caribous over the next couple of days.

Snowpack Summary

We're dealing with a complex snowpack in the Caribou Mountains at this time. New snow will load the regions persistent weak layers which could reach a critical point tomorrow.Up to 160cm of snow can be found at treeline. Alpine snow depths vary between 1 to 2m. New snow is falling on a settling upper snow pack. 50 to 80cm of snow now sits on a variety of old weak layers from early December: surface hoar, faceted snow, and/or a crust. Previously warm temps have formed a cohesive mid pack on top of surface hoar or facets from late November. Snowpack tests results have been varied but some are showing this layer pop with medium loads. In many places we're still dealing with a relatively thin snowpack so there's not a whole lot of snow between riders and the sugary snow (facets) near the ground.

Problems

Storm Slabs

Expect touchy soft slabs to develop as the temperatures warm through the storm. Strong winds will likely form reactive pockets of windslab in ridgetop and cross loaded lee features in the alpine and at treeline.

Avoid freshly wind loaded features.>Choose well supported terrain without convexities.>Avoid slopes with glide cracks.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 4

Persistent Slabs

Persistent weak layers exist in the upper meter of the snowpack. With the additional load of the forecast snow they may be susceptible to triggering, creating large destructive avalanches.

Be aware of the potential for large, deep avalanches.>Use conservative route selection, stick to moderate angled terrain with low consequence.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 4

Deep Persistent Slabs

In areas with a shallower snowpack it may be possible to trigger larger avalanche on or close to the ground.

Avoid rock outcroppings, steep convexities and anywhere the snowpack feels thinner than average.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Dec 26th, 2013 2:00PM