Bulletin d’avalanche

Lizard-Flathead

Mar 10 – 11, 2021Avalanche Canada
Voir sur la carte
Archivé · expiré 6 years ago

Danger d’avalanche

Fri
Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Buried weak layers remain possible to be triggered, where they still exist.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3

    Two weak layers may exist between 30 and 100 cm deep. Widespread avalanche activity has already occurred on the layers, but they could still be triggered anywhere they haven't already failed. Look for signs of instability and continue treating the snowpack as suspect if you are uncertain whether the layer is still present in your riding area.

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

TUESDAY NIGHT: Clear skies, 20 km/h southwest wind, alpine temperature -8 C.

WEDNESDAY: Increasing clouds with late-afternoon snowfall, accumulation 1 to 3 cm, 20 km/h southwest wind, alpine temperature -6 C, freezing level 1500 m.

THURSDAY: Morning clouds then clearing, 20 km/h southwest wind, alpine temperature -6 C, freezing level rising to 1600 m.

FRIDAY: Clear skies, 20 km/h southwest wind, alpine temperature -4 C, freezing level rising to 1900 m.

Avalanche Summary

No avalanches were observed on the weekend or Monday, besides some small loose avalanche out of steep terrain. The most recent persistent slab avalanche activity was on Friday, being triggered by explosives.

Snowpack Summary

A few centimetres of snow overlies a thick melt-freeze crust in many areas, with the exception being on north aspects above around 1700 m. Wind slabs may still exist on northerly aspects at alpine and treeline elevations. On solar aspects and below the freezing level, the snow may moisten during the heat of the day.

Around 30 to 50 cm of snow overlies a variety of old interfaces that formed in mid-February. There hasn't been recent avalanche activity on this layer, but it remains possible to be triggered where it exists. The more active layer was buried late January, which is found 50 to 100 cm deep. This layer is mostly composed of sugary faceted grains, hard wind pressed snow, feathery surface hoar in wind-sheltered locations, and a melt-freeze crust on steep solar aspects. Periodic avalanches continue to be triggered on this. Check out this MIN for photos of the positioning of these layers in the snowpack.

Terrain and Travel

  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

Régions couvertes