Bollettino valanghe

Purcells

Jan 19 – 20, 2015Avalanche Canada
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Archiviato · scaduto 12 years ago

Pericolo valanghe

Wed
Thu
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Recent storm totals vary across the region. Pay close attention to how much snow fell in your area as this will affect your localized hazard. For more details, check our latest Blog Post: http://www.avalanche.ca/blogs/VLsBsCgAACYAJdfM/mid-jan-sh

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2–4
    Reports suggest the mid-December weak layer has become less likely to trigger. That said, the weight of the new snow or an avalanche in motion may increase the reactivity of this potentially destructive layer.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–4
    Snow and wind over the weekend has added size and reactivity to a developing storm slab which seems most reactive at higher elevations. Prolonged reactivity is expected due to underlying weak crystals.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Expect generally cloudy skies with occasional sunny breaks on Tuesday and Wednesday as a dry weak ridge develops over the southern half of the province. By Thursday it looks like the ridge may break-down somewhat allowing for moist pacific system to enter the region from the northwest. If this happens, accumulations will likely be light. Winds should remain light to moderate from the west-northwest. Freezing levels will hover around 800m on Tuesday and Wednesday, and then rise to about 1000m on Thursday.

Avalanche Summary

No avalanche activity was reported in recent days. I'm very confident that was due to a lack of observations rather than actual conditions. In deeper snowpack areas I'm sure there was a decent round of storm slab activity failing on the recently buried surface hoar. Due to the persistent nature of these crystals, I expect continued human triggered storm slab avalanche activity in these areas. Avalanche activity is generally unlikely on deeper persistent weaknesses. That said, a surface avalanche in motion could "step down" to a deeper, more destructive layer.

Snowpack Summary

Between 15cm and 40cm of recent snowfall has buried widespread 10-20mm surface hoar and a sun crust on steep sun exposed slopes. Strong winds have blown these accumulations into deeper deposits in higher elevation terrain. Due to the underlying surface hoar, I would expect continued touchy conditions, especially in areas where the recent snowfall exists as a cohesive slab.The mid-December surface hoar/crust layer is typically down 60-120cm below the surface. The reactivity of this persistent weak layer appears to be quite variable but still has the potential for large, destructive avalanches in some areas. The layer appears to be the most reactive at and below treeline. The mid-Nov weak layer is near the bottom of the snowpack but has generally become inactive.

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