Avalanche Forecast

Issued: Jan 21st, 2015 8:03AM

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

Peter, Avalanche Canada

Northwest Inland.

The last system dumped more snow than forecast to parts of the region. If this pattern continues expect periods of HIGH avalanche danger over the next few days.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Synopsis: We could see a short lull in the weather on Thursday before another strong frontal system hits the North Coast on Friday. Expect 5-10 cm (mm) tonight and Thursday followed by 15-25 cm (mm) on Friday. The freezing level should be around 1600 m and winds are strong from the southwest. Saturday looks like another lull in intensity but we could still see 5-15 cm with a freezing level a couple hundred metres lower.

Avalanche Summary

Periods of heavy snow or rain, strong ridge winds, and warming will probably tip off a natural avalanche cycle in parts of the region. We could see wet activity at lower elevations with storm/wind slabs where snow accumulates. There is also potential for deep persistent weaknesses to be overloaded producing isolated very large and deep slides. This pattern should continue for most of the week.

Snowpack Summary

Periods of heavy snow (or rain at lower elevations) and strong southerly ridge winds are building deep and dense storm/wind slabs. The slab may be 'upside down' with moist or wet snow blanketing the previous dry low-density snow. A surface hoar layer, buried at the start of January in the northern part of the region, may be around 40-60 cm deep now. In the mid-pack, a crust weakness buried in mid-December seems to have fallen off most operators' radar for now. Near the base of the snowpack is a November crust-facet combination that could remain problematic, especially in shallower snowpack areas with heavy loading and warming this week.

Problems

Storm Slabs

Weaknesses could exist within or under the new storm snow. Expect deep and dense wind slabs to form in exposed NW-NE facing terrain.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Stick to simple terrain and be aware of what is above you at all times.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Wet Slabs

It will probably be pretty wet at lower elevations this week (below ~ 1500m). Steer clear of slopes with open glide cracks and terrain traps.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Deep Persistent Slabs

Heavy loading from snow and/or rain could trigger deep persistent weaknesses and produce isolated very large avalanches.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 6

Valid until: Jan 22nd, 2015 2:00PM