Avalanche Forecast

Issued: Jan 29th, 2016 7:56AM

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

ccampbell, Avalanche Canada

Cariboos.

Patience and diligence may be required to resist venturing into complex terrain as the snowpack settles and adjusts to the recent load and warming.

Summary

Confidence

High

Weather Forecast

SATURDAY: A mix of sun and cloud with isolated light flurries. Freezing levels around 1200m and light southwesterly winds. SUNDAY: A mix of sun and cloud and mainly dry with freezing levels dropping below valley bottoms and light variable winds. MONDAY: A mix of sun and cloud with isolated light flurries. Freezing levels in valley bottoms and light southwesterly winds.

Avalanche Summary

Reports from Thursday include natural wet slabs up to Size 2 at lower elevations, but observations were limited. On Sunday, a skier remotely trigger a size 1 avalanche on a NW aspect from 10m away. The slab was 60cm thick which suggests that it failed on the early January surface hoar layer. Natural loose avalanches up to size 2 were also reported from extreme terrain and did not trigger any slabs below. Widespread natural avalanche activity up to size 3 was reported on Friday and Saturday.

Snowpack Summary

Recent storm totals and freezing levels across the region have been highly variable with some areas receiving over 40mm of precipitation in the past few days with freezing levels spiking over 1700m, while others stayed relatively cool and dry. Weaknesses exist within and under this recent storm snow, which is particularly deep and touchy on wind-loaded slopes in alpine and exposed treeline areas, and bonding poorly to recently buried surface hoar, facets, and/or a crust at lower elevations and south aspects. The persistent weak layer of buried surface hoar, sun crusts, rime crusts and/or facets that was buried in early January is now down around a metre. The overlying slab remains primed for triggering and is especially touchy at and below treeline. The mid and lower snowpack below these layers is generally well-settled and strong, with any old weak layers considered dormant for now. Snowpack depths are variable and shallow snowpack areas may have weak facetted crystals near the ground.

Problems

Storm Slabs

Fresh storm and wind slabs are sensitive to human triggers an particulary touchy where they are bonding poorly to recently buried surface hoar or crust.

The new snow will require several days to settle and stabilize.>Be cautious as you transition into wind affected terrain. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Surface hoar buried at the beginning on January remains a concern for human triggers. The potential for widespread propagation and remote triggering makes this persistent slab particularly tricky to manage.

Use conservative route selection and be aware of the potential for remote triggering. >Extra caution required in open terrain features at and below treeline. >Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Jan 30th, 2016 2:00PM