Avalanche Forecast

Issued: Jan 15th, 2017 4:37PM

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

cgarritty, Avalanche Canada

Cariboos.

Watch for signs of instability as warm temperatures arrive in advance of Monday night's storm.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

Monday: Flurries bringing 10-15cm of new snow beginning late in the day. Winds moderate from the south. Freezing level rising to 1000 metres with alpine temperatures to -6 Tuesday: Flurries and periods of snow delivering 10-20 cm of new snow. Winds moderate from the south. Freezing level rising to 1400 metres with alpine temperatures of -3. Wednesday: Flurries and periods of snow delivering 10-15 cm of new snow. Winds moderate gusting to extreme from the south. Freezing level rising to 1700 metres with alpine temperatures around -1.

Avalanche Summary

No new avalanches were observed on Saturday. Friday's reports indicated Size 1-1.5 wind slab avalanches were continuing to run naturally in steep terrain, with the most recent activity observed on north aspects near Valemount. Aside from wind slab and persistent slab problems, additional caution is advised in steep terrain where loose snow sluffing may present an unexpected hazard.

Snowpack Summary

Recent cold and clear weather has promoted both faceting of surface snow as well as the growth of surface hoar that has been reported to be up to 7mm in size in sheltered areas below treeline. Below the surface, our recent storm snow was redistributed by moderate to strong southwest and more recent northerly winds in exposed upper areas. In deeper snowpack parts of the region, the mid-December facet layer lies up to 120 cm below the surface. In these areas, professionals feel this layer has generally gained considerable strength. In shallower areas, particularly those in the southeast (Allen Creek), North (Sugarbowl) and likely some western areas around Quesnel and Barkerville, the snowpack is likely a lot more suspect, with a thicker, more pronounced facet layer buried only 50-60 cm below the surface. In shallow snowpack areas such as these, recent cold temperatures have had the effect of weakening the entire snowpack, not just its upper layers. A careful evaluation of this facet layer is strongly advised before to any push into steeper terrain in a shallow snowpack area.

Problems

Wind Slabs

Recent winds formed touchy wind slabs on many aspects in exposed alpine and treeline areas. Expect these to remain reactive over the short term and be aware of the potential for wind slab avalanches to trigger deeper weaknesses in the snowpack.

Avoid areas where the snow feels stiff or slabby.Be alert to conditions that change with aspect and elevation.Watch for signs of instability such as whumpfing, cracking, or loose snow sluffing.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

This layer has gained strength in many areas, but triggering an avalanche on facets buried in mid-December may still be possible in shallow snowpack parts of the region. Dig down and test for weaknesses before committing to larger terrain features.

Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Jan 16th, 2017 2:00PM