Bulletin d’avalanche

North Columbia

Mar 21 – 22, 2019Avalanche Canada
Voir sur la carte
Archivé · expiré 8 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
Ouvrir la carte complète

Points saillants

The hot and sunny weather persists on Friday. The danger will be the highest when the day heats up. Set up your plan to avoid sun-exposed slopes and overhead exposure during the heat of the day.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–3
    A slab of snow may be poorly bonded to weak, sugary faceted snow or a melt-freeze crust. The warm temperature and strong sun has increased the likelihood of triggering a slab avalanche by humans, cornices, and naturally.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–2.5
    The upper snowpack will likely destabilize in the day with hot and sunny weather, producing loose wet avalanches. The most problematic time is with maximum warming during afternoon hours. Best to avoid sun-exposed slopes during the heat of the day.

Confidence

High -

Weather Forecast

THURSDAY NIGHT: Clear skies, light southeast wind, alpine temperature 5 C, freezing level 3000 m.FRIDAY: Partly cloudy skies, light southeast wind, alpine temperature 4 C, freezing level 2800 m.SATURDAY: Cloudy with light snow in the alpine and rain below, accumulation 2 to 5 cm, light west wind, alpine temperature 0 C, freezing level 2000 m.SUNDAY: Cloudy with snowfall, accumulation 1 to 3 cm, light southeast wind, alpine temperature -3 C, freezing level 1600 m.

Avalanche Summary

Many wet loose avalanches were observed between Sunday and Wednesday. They were large (up to size 3), occurred mostly on southeast to southwest aspects, and at all elevations. A couple persistent slab avalanches were also triggered by skiers, 40 to 80 cm deep and on south and north aspects in alpine terrain. This avalanche cycle may continue on Friday on sun-exposed slopes, as temperatures remain exceptionally warm and the sun shines strong. The cycle should end on Saturday, as freezing levels drop and cloudy skies prevail.

Snowpack Summary

The warm air and sunny skies have produced wet snow to ridge top on southerly aspects and up to around 1800 m on northerly aspects. The upper 40 to 60 cm of snow may slide easily during the day on sun-exposed slopes, either as loose wet snow or as a cohesive slab, as this snow sits over weak faceted grains or a melt-freeze crust. The wet snow may freeze into a melt-freeze crust overnight.Below treeline, a weak layer of faceted grains and/or feathery surface hoar crystals may be found around 70 to 120 cm deep. Although this layer has been dormant for a few weeks, the current warm conditions may awaken this layer. Steep cutblocks and large open glades at lower elevations are the most likely places to trigger this layer.The lower snowpack is generally consolidated and strong. The exception is around thin, rocky areas in the alpine, where the snowpack is composed of faceted snow. The warm air and sunny skies could trigger very large avalanches that could run to the valley bottom.

Régions couvertes