Bulletin d’avalanche

South Columbia

Mar 2 – 3, 2016Avalanche Canada
Voir sur la carte
Archivé · expiré 11 years ago

Danger d’avalanche

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

Points saillants

Touchy and growing storm slabs will keep avalanche danger elevated this week. Riding should be great, but a conservative approach is recommended. Stick to simple terrain.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–5
    Heavier triggers such as cornice falls, groups of people, or smaller avalanches stepping down, or lighter triggers (such as a person) in the wrong spot may be enough load to trigger a crust and/or surface hoar layer down around a metre.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–4
    Fresh storm slabs are primed for human triggering. Particularly touchy wind slabs are lurking below ridge crests, behind terrain features and in cross loaded gullies.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Saturday

Weather Forecast

THURSDAY: Periods of snow with 5-10cm of accumulation expected overnight Wednesday and throughout the day Thursday. Freezing levels reaching 1800m with moderate to strong southwesterly ridgetop winds. FRIDAY: A mix of sun and cloud in the morning with light precipitation starting late in the day. Freezing levels reaching 2000m with moderate to strong southwesterly ridgetop winds. SATURDAY: Cloudy with flurries bringing another 5-15cm. Freezing levels steady around 2000m and strong southwesterly ridgetop winds.

Avalanche Summary

Reports from Tuesday include more evidence of the widespread natural storm and wind slab avalanche cycle early Monday primarily in the Monashee Mtns., with avalanches up to Size 3 running on surface hoar buried late February. Continued isolated natural avalanche activity occurred on Tuesday primarily in alpine areas with avalanches observed up to Size 2 in response to loading from fresh snow and wind. Elsewhere, 15-40cm thick fresh storm and wind slabs were highly reactive to human triggers with several direct and remotely triggered avalanches up to Size 2. These fresh storm and wind slabs should increase in size and sensitivity and become much more widespread as they build throughout the week.

Snowpack Summary

10-20cm of fresh snow adds to the now 30-60cm thick storm slabs, which are bonding poorly to on a crust on previously sun-exposed slopes and surface hoar on shady and sheltered slopes. Thicker and touchier wind slabs are lurking throughout exposed terrain at and above treeline. A weak layer of surface hoar and/or a sun crust buried February 21 is now close to a metre below the surface. Where it exists, this layer may become reactive to human triggers as the overlying slab develops. The surface hoar and/or crust layer buried February 10 is likely down over a metre. This layer was less reactive over the weekend with cooler temperatures, but remains a concern for large triggers like cornice falls or a smaller avalanches stepping down. Cornices are large and potentially weak and should be avoided where possible.

Régions couvertes