Bulletin d’avalanche

Waterton Lakes

Feb 13 – 16, 2015Parks Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

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

A few cm over the week and warm temperatures have improved travel conditions however the avalanche hazard will not drop until the temperatures do.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    At treeline and above expect to find superficial slabs formed by SW winds this week.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    These slabs that formed last weekend are sitting on a firm surface or crust 50 to 80cm deep. With continued warm conditions these slabs remain possible to trigger in many areas. The deep persistent layers could also be triggered in isolated areas.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Below 2000m surface crusts are all that there is to hold the lid on a wet snowpack. Without a solid freeze these crusts remain weak and will break down quickly with further heating. Loose wet activity may also trigger wet slabs in isolated locations.

Weather Forecast

After a week freeze tonight, warm conditions with a freezing level around 2000m will persist through Saturday. Sun on Friday could weaken snow on solar slopes.  10mm of precip expected midday Saturday. We look forward to the first good freeze in a while on Saturday night followed by mainly dry weather into the start of the week.

Snowpack Summary

Above 2000m 5 to 10cm and thin windslabs cap the 50 to 80 cm slab above the Jan 31 crust. Rain has created surface crusts below 2000m and the entire snowpack remains moist with warm temps allowing poor recovery below 1900m. The Dec 13 layer down about 1m average is still a concern in high shaded terrain where there are no strong crusts above it.

Avalanche Summary

Cornice fall triggered thin windslabs that were enough of a load to pull a 100m wide slab out of the hanging face above Wall lake sometime in the last 36 hrs. This slab was 60 to 100cm deep and likely ran on the Jan 31 interface.

Confidence

Freezing levels are uncertain

Régions couvertes