Bulletin d’avalanche

South Coast Inland

Mar 1 – 2, 2021Avalanche Canada
Voir sur la carte
Archivé · expiré 6 years ago

Danger d’avalanche

Wed
Thu
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
Ouvrir la carte complète

Points saillants

A bit of new snow with strong wind will keep wind slabs fresh on Monday. Keep an eye out for wind affected snow on atypical aspects and lower-than-usual elevations due to recent variable wind direction and elevation.

Problèmes avalancheux

  • Wind Slabs

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

    Strong winds may spill over into low elevations Sunday night and Monday so watch for freshly wind affected snow lower down on the mountain than usual. Recent wind has varied in direction so wind slabs may be found on all aspects.

    Cornices are likely growing as well. Fresh, unsupported tabs breaking off can be dangerous on their own, they can also act as triggers on slopes below.

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

Sunday night: Flurries bringing a trace of snow. Strong southwesterly winds affecting all elevations. Freezing level around 1000 m.

Monday: Up to 5 cm new snow. Strong southwesterly winds affecting all elevations. Freezing level 1500 m.

Tuesday: Up to 5 cm new snow overnight then clearing. Moderate southwesterly winds. Freezing level 1000 m.

Wednesday: Mix of sun and cloud. Light to moderate southwesterly winds. Freezing level 1300 m.

Avalanche Summary

Pinwheeling and small loose wet sluffing was observed on steep sun exposed slopes on Saturday afternoon.

Otherwise, recent avalanche activity around and north of Duffey Lake has been limited to loose dry sluffing and small human triggered soft slabs in the recent storm snow. This MIN is a great reminder that terrain traps can increase the consequences of even small avalanches. Glad everyone is unharmed.

Reports from the Coquihalla indicate quite limited natural storm slab activity during the storm with only a couple of size 2's noted. We had reports of plenty of skier traffic in the Coquihalla area on Saturday but no avalanches.

Snowpack Summary

Recent storm snow has been variable across the region, the Coquihalla receiving around 60-80 cm and other areas in the 15-30 cm range. This snow appears to be bonding well to underlying surfaces including crusts on steep solar aspects and below 1500 m in the Coquihalla area.

At upper elevations, recent snow is wind affected and is likely undergoing continued transport as winds pick up into Sunday morning. Wind direction has been predominantly westerly but may also have southerly or northerly components, depending on elevation.

A weak layer composed of a crust, facets or surface hoar depending on elevation/aspect is now down 70-120 cm. This layer, buried in late January, continues to be noted in snowpack tests with mixed results. There have been no recent avalanches reported on this layer. Large triggers, such as an avalanche in motion, cornice fall, or intense loading from snow/ wind and/or a rapid rise in temperature can awaken these deeper weak layers.

The lower snowpack is well settled and strong in most areas.

Terrain and Travel

  • Wind slabs are most reactive during their formation.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Régions couvertes