Bollettino valanghe

Kootenay Boundary

Mar 17 – 18, 2015Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 12 years ago

Pericolo valanghe

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

In sintesi

Lingering storm instabilities remain a concern, especially in the alpine. Avoid steep, wind loaded features and large, unsupported slopes. Use extra caution on sun-exposed slopes during the heat of the afternoon.

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–4
    20-30cm thick storm slabs sit over a new rain crust. At lower elevations or on sunny slopes, these slabs may be moist or wet. At higher elevations, the slabs should be most reactive in wind loaded areas or on steep, unsupported terrain features.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–3
    Solar radiation and daytime warming will likely deteriorate the upper snowpack initiating loose wet avalanches. Overhead hazards like cornices could also fail and trigger slab avalanches on the slopes below.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Light precipitation (2-4mm) can be expected for much of the region Tuesday overnight and Wednesday morning. By Wednesday afternoon the clouds should break and sunny periods are possible. Freezing levels should reach around 2000m Wednesday afternoon and alpine winds should be moderate from the NW. On Thursday, a warm storm system reaches the south coast. There is currently quite a bit of uncertainty regarding the timing and track of the system into the interior regions. For the KB region, it is currently looking like unsettled conditions for Thursday with mainly cloudy conditions and light scattered precipitation. Freezing levels should again reach around 2000m and alpine winds may be moderate or strong from the SW. On Friday, light precipitation is expected but amounts are uncertain. Freezing levels may climb to over 2500m.

Avalanche Summary

On Monday, a natural size 2 avalanche was reported from a steep wind-loaded slope, ski cuts produced several size 1 soft storm slabs, and a skier triggered a size 1.5 storm slab. Lots of natural loose wet avalanches up to size 2 were reported from all aspects in the afternoon. On Wednesday, loose wet avalanches are possible during the heat of the afternoon, especially on sun-exposed slopes. Human-triggering of storm slabs remains a major concern, especially in the alpine. Wind-loaded features and steep, unsupported slopes are the most likely areas to trigger an avalanche.

Snowpack Summary

Heavy rain on Saturday soaked the snowpack up to ridge tops. On Sunday, heavy snowfall (up to 35cm) and southwest winds developed new storm slabs that are still reactive to human-triggering. The new snow sits on the mid-March rain crust that formed during the rain event on Saturday. The mid-Feb layer was down around 20cm before the rain event and there is currently uncertainty as to the status of this layer. Older deeply buried persistent weak layers still exist in the snowpack. These layers have not been reactive lately but the extremes of warm weather followed by heavy loading from rain and snow make it difficult to assess how the snowpack will respond.

Regioni coperte