Avalanche forecast

Cariboos

Jan 19 – 20, 2013Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–5
    Recent wind event and new snow has formed new wind slabs on lee slopes in the alpine and at treeline.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–5
    Triggering persistent slabs is becoming less likely, but a cautious approach is still advised. Carefully assess steep south-facing slopes and slopes below about 1900 m, where persistent weaknesses are most likely to be lurking.

Avalanche Summary

Several recent natural slab avalanches up to size 1.5 were reported which would have released in the new storm snow. A glide crack released to the ground producing a size 2.5 was also reported on a SW aspect.

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Saturday night and Sunday:  Ridge of high pressure continues to dominate for the whole period. No precipitation, mild temperatures, scattered clouds and valley clouds and moderate Westerly winds becoming light on Sunday.Monday: Similar conditions with warmer temperatures and freezing level rising to 1100 m. Tuesday: Dry conditions persist, light S winds and freezing level around 1000 m.

Snowpack Summary

15-20 cm of new snow fell with strong NW switching to SW winds creating windslabs on lee side in alpine and at treeline. The new windslabs were producing some sudden planar tests results and were reactive to skier traffic. The forecasted mild temperatures and reduced wind transport should give them a chance to improve the bond with the underlying surface. Cornice growth has also been observed. The storm snow sits above surface hoar (found especially below treeline in sheltered areas down around 40 cm), a sun crust on steep S to SW -facing slopes and facets. The distribution of these weaknesses is patchy, but where they exist, it may still be possible to trigger a large avalanche with the weight of a person or snowmobile. Indeed, snow tests showed sudden planar results in the easy to moderate range. A strong mid-pack overlies a weak facet/crust layer near the base of the snowpack, which is now considered inactive.

Regions covered