Bollettino valanghe

Lizard-Flathead

Mar 12 – 13, 2024Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 3 years ago

Pericolo valanghe

Thu
Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato

In sintesi

Stick to mellow terrain, and avoid traveling in or under large, open slopes

Wind slabs are reactive to human triggers and buried weak layers remain capable of producing very large avalanches

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–2

    Reactive wind slabs likely exist on north and east facing slopes around ridgelines. Small wind slabs could step down to deeper weak layers producing very large avalanches.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    2–3

    Avoid areas where the snowpack thins, like steep, rocky start zones at treeline and alpine elevations. Weak layers are more easily triggered here.

Confidence

Moderate

Avalanche Summary

On Monday, a few natural and explosive triggered avalanches (up to size 2) were reported. Some of these avalanches failed on persistent weak layers.

Over the weekend, large persistent slab avalanches continued, triggered by riders and naturally by cornice falls onto the slope below. A fatal avalanche occurred in nearby Kananaskis Country on Sunday, where a similar snowpack structure exists.

Snowpack Summary

Around 30-40 cm of recent storm snow has fallen and been redistributed by wind into deeper deposits on north and east facing slopes. Recently formed wind slabs are not sticking well to the old surface. This is a crust on sun affected slopes, surface hoar in sheltered terrain, and wind affected snow in exposed areas.

A widespread crust with weak facets above remains a concerning layer for human triggering. Buried 80-150 cm deep, this layer has produced very large avalanche activity this week.

The snowpack below the crust is generally strong.

Weather Summary

Tuesday Night

Mostly cloudy. 5-10 cm of snow expected, with a possibility of higher localized snowfall. Light southwest ridgetop wind. Freezing level falling to 1500 m, with treeline low around -7 °C.

Wednesday

Mostly cloudy. Localised snowfall, up to 5 cm. Light southwest through northwest ridgetop wind. Freezing level rising to 1800 m, with treeline high around -2 °C.

Thursday

Mostly sunny. 0-2 cm of snow expected. Light west or northwest ridgetop wind. Freezing level at valley bottom overnight, rising to 1800 m. Treeline high around -1 °C.

Friday

Sunny. No new snow expected. Light west or northwest ridgetop wind. Freezing level at valley bottom overnight, rising to 2900 m. Treeline high around 5 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Remote triggering is a concern, watch out for adjacent and overhead slopes.
  • Cornice failures could trigger very large and destructive avalanches.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Regioni coperte