Bulletin d’avalanche

Jasper

Mar 22 – 23, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Spring like conditions persist into Thursday afternoon, start early and finish early as solar warming is having the strongest effect typically by mid-afternoon.

The sun is heating up cornices, cliffs and steep rocky features triggering wet loose avalanches and deeper slab instabilities.

Ice climbers, be cautious of narrow gullies that act as terrain traps, as even small slides can have significant consequences.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2.5

    The 20cm of surface snow from March 13th has been periodically blown around, redistributed, settled, and has combined with the larger snowpack structure for the most part. There is a cornucopia of interfaces throughout the snowpack depending on aspect, elevation, and local terrain influences. There have been a few avalanches this past week which appeared to have stepped down to multiple layers. Sun will increase potential reactivity.

  • Loose Wet

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

    Loose wet snow avalanche activity is expected to slow down into the weekend as a new front is approaching with clouds, precipitation, and cooling temperatures. These types of avalanches can be what initiate larger slab avalanches.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1.5–3.5

    The bottom of the snow pack is inherently weak with well developed Facets and Depth Hoar. Persistent slab avalanches have stepped down to the deep persistent slab since the last storm meaning large triggers can influence this basal weakness.

Confidence

Moderate

Avalanche Summary

Several wet loose avalanches observed in the last week occurring mid to late afternoon at all elevations southerly aspects with many stepping down to the basal weakness or triggering persistent and deep persistent slab avalanches. Large to very large deep persistent slabs have been observed throughout the region, generally triggered by a small loose wet slide, or a cornice fall.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

Sun crust on solar aspects at all elevations breaking down by early to mid afternoon. Approximately 20-30cm down is a buried sun crust at low elevations on steep southerly slopes and a surface facet layer in sheltered terrain. The mid-pack is 40 to 80cm of supportive facetted snow. Near the ground it is generally weak with large facets and depth hoar.

Weather Summary

On Thursday, expect sun with cloudy periods and freezing levels at 1600 m with light southwest winds. Late Thursday, the ridge of high pressure will give way to a more active pattern bringing 7 cm of snow, light southwesterly winds and freezing levels to 1500 m by the end of Friday.Saturday, expect scattered flurries with up to 5 cm accumulation and winds switching to northwesterly, freezing levels at 1500 m.

Detailed weather forecasts from Avalanche Canada: https://avalanche.ca/weather/forecast

Terrain and Travel Advice

  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Be alert to conditions that change with elevation and sun exposure.
  • Avoid exposure to steep sun exposed slopes.

Régions couvertes