Bulletin d’avalanche

Jasper

Mar 21 – 22, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

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

The region is trending towards spring like conditions. 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 increasing as afternoons are getting dramatically warm. These types of avalanches can be what initiate larger slab avalanches. Temperatures are ranging from -15 at night to +8 in the afternoon.

  • 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

High

Avalanche Summary

Several wet loose avalanches observed on Monday occurring mid to late afternoon on Sunday - all elevations southerly aspects with many stepping down to the basal weakness or triggering persistent and deep persistent slab avalanches. One size 3 deep persistent slab on Sunset peak southwest aspect propagated across half of a large alpine bowl feature. Afternoon loose wet cycle continues in the Coleman area 93N just south of Weeping Wall with avalanches reaching the ditch and some spilling onto the highway.

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

A ridge of high pressure will remain the dominant weather feature through late Thursday. Wednesday will be sunny with an alpine temperature high of -5 C and light westerly ridge top winds, freezing levels forecast at 1900 m. Late Thursday the ridge will give way to a more active pattern with light precipitation forecast for Friday.

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