Bollettino valanghe

North Columbia

Apr 18 – 19, 2023Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 3 years ago

Pericolo valanghe

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

In sintesi

Riders must manage various avalanche concerns that vary by elevation and aspect. Observe your local conditions and let that inform your terrain choices.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–3

    A layer buried on April 1, down roughly 50 to 100 cm from the surface, appears to be most reactive on solar tilted slopes where surface hoar may sit on a hard melt-freeze crust.

    This layer is the culprit for the string of close calls over the last week and Saturdays fatal accident at Thunderwater Lake.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Scattered flurries continue to build storm slabs and may still need time to bond to underlying surfaces. Be especially cautious at higher elevations, near ridges and mountain tops were wind has likely increased slab depth and reactivity.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2.5–4

    A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth.

    Suspect terrain includes steep, shallow, and rocky terrain where the snowpack varies between thin and thick.

Confidence

Moderate

Avalanche Summary

Avalanche activity appears to be slowing. However, many natural and human-triggered avalanches have been reported over the last week. Many of these are sliding on recently buried melt-freeze crusts, including a fatal avalanche in the western Purcells and a close call near Revelstoke.

Snowpack Summary

Dry, powder snow remains at higher elevations on north-facing terrain. While melt-freeze crusts or moist snow are likely to be found on steep solar slopes and at lower elevations.

A layer of surface hoar persists down roughly 50 to 100 cm from the surface. In all but true north-facing slopes the surface hoar likely sits on a melt-freeze crust and is responsible for numerous recent avalanches, some with surprisingly wide propagation.

The mid-snowpack is strong. However, the November depth hoar remains at the base of the snowpack and remains a concern in rocky, shallow, variable depth snowpack areas at treeline and above.

Weather Summary

Tuesday night

Mostly cloudy, with trace amounts of snow. Light west ridgetop winds. Treeline temperatures around -5 C. Freezing levels 500 m.

Wednesday

Cloudy with scattered flurries and a trace of snow. Light west ridgetop winds. Treeline temperatures around -5 C. Freezing level 1600 m.

Thursday

Cloudy with sunny periods in the afternoon. Light west ridgetop winds. Treeline temperatures 0 to -5 C. Freezing level 1900 m.

Friday

Mix of sun and cloud. Light ridgetop winds. Treeline temperatures 0 to -5 C. Freezing level 1900 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be alert to conditions that change with elevation and sun exposure.
  • Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
  • If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.

Regioni coperte