Bulletin d’avalanche

North Columbia

Feb 15 – 16, 2023Avalanche Canada
Voir sur la carte
Archivé · expiré 4 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
Ouvrir la carte complète

Points saillants

Wind slabs are becoming more difficult to trigger, don't commit to a steep slope if the snow looks wind affected or feels dense or stiff. Back off if you see evidence of nearby avalanches, or if you notice cracks appearing in the snow surface or other signs of instability.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2.5

    Wind slabs continue to be reactive to human triggers, this problem is found at upper elevations directly lee of ridges.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–3

    Numerous problematic weak layers exist in the top meter of the snowpack. Recent large persistent slab avalanche observations are strong evidence that these layers are still an active concern in this region. Recent avalanches have been triggered by a mix of large loads like cornices but also remote triggers.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2.5–4

    A layer of large and weak facets sits near the base of the snowpack. This layer continues on a sporadic basis to produce very large avalanches that can travel far. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain, or by triggering a smaller avalanche that could step down to this layer. Your best defence is to stay diligent in choosing low-consequence terrain away from overhead exposure.

Confidence

Moderate

Avalanche Summary

Natural and human-triggered wind slabs continue throughout the region.

Sporadic avalanche activity continues on persistent weak layers buried in January. These avalanches continue to remind us that these layers are taking time to heal and continue to require diligence.

Going forward wind slabs are becoming more difficult to trigger but still require some time to bond to previous surfaces.

Snowpack Summary

Recent snow has been redistributed into wind slabs directly lee of ridges at treeline and alpine elevations. The most recent snow is generally bonding to previous surfaces of old wind slabs and soft snow in sheltered terrain.

Two layers of surface hoar which formed in early January are now roughly 80 to 140 cm deep. Although snowpack tests are indicating strengthening here, these weak layers are still being watched closely by local operators.

Large and weak facets from November are near the base of the snowpack and although avalanche activity on this basal weakness has been on a bit of a decline, it still figures prominently in the assessments and terrain use (and avoidance) of professionals throughout the region.

Weather Summary

Tuesday night

Mostly clear, trace accumulations, 5 to 10 km/h southwest winds, treeline temperatures-10 °C

Wednesday

A mix of sun and cloud, 5 to 10 km/h west winds, treeline temperatures around -10 °C.

Thursday

Mainly cloudy, 5 to 10 km/h southwest winds, flurries beginning in the evening, 2 to 5 cm new snow, treeline temperatures -7 °C.

Friday

Mainly cloudy, flurries 5 to 10 cm of new snow, 20 to 30 km/h winds, treeline temperatures -8 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.
  • Be especially cautious as you transition into wind affected terrain.
  • Watch for areas of hard wind slab on alpine features.

Régions couvertes