Bulletin d’avalanche

Purcells

Nov 23 – 25, 2019Avalanche Canada
Voir sur la carte
Archivé · expiré 7 years ago

Danger d’avalanche

Mon
Tue
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Strong southwest wind combined with up to 20 cm of new snow is expected to form wind slabs which will be most problematic near ridge crest. The weak & highly variable snowpack will likely need time to adjust. Conservative terrain selection is prudent Sunday.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2

    Alpine elevations in the North of the region could see as much as 20 cm of new snow by Sunday morning combined with strong southwest wind. This is expected to form wind slabs which will likely be most prevalent immediately lee of ridge crest.

  • Persistent Slabs

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

    Very little is known about some of the crusts in the lower snowpack at this time, but current riding conditions are likely to push folks into the alpine where there is potential for riders to initiate avalanches failing on one of the more deeply buried crusts.

Confidence

Low - Uncertainties in both the snowpack structure and the weather forecast limit our confidence.

Weather Forecast

Saturday Night’s storm should offer the Purcells (especially the northern section) a nice re-fresh before we move into a period of high pressure next week.

SATURDAY NIGHT: Freezing level around 1100 m, moderate to strong west/southwest wind, 5 to 20 cm of snow possible.

SUNDAY: Broken cloud cover, freezing level around 1100 m, light to moderate northwest wind, 1 to 5 cm of snow possible.

MONDAY: Broken cloud cover, freezing level around 700 m, light variable wind, trace of snow possible.

TUESDAY: Scattered cloud cover, freezing level at valley bottom, calm, no significant precipitation expected.

Avalanche Summary

No recent avalanche activity has been reported. A natural avalanche cycle is possible late Saturday Night into Sunday as strong southwest wind and up to 20 cm of snow is forecast.

Snowpack Summary

Winter is slowly creeping down to the valley, but avalanche hazard is largely confined to the alpine at this time. Snowpack depths range from 10 to 100 cm. The young snowpack is higly variable due to previous wind transport and areas of shallow snow which are highly faceted. Most treeline and below treeline areas are probably below threshold for avalanches at this time. A pottentially problematic melt freeze crust from late October can be found above basal facets in the lower snowpack. There's a great summary of current conditions in the Golden area here.

Régions couvertes