Bulletin d’avalanche

Lizard-Flathead

Jan 15 – 16, 2022Avalanche Canada
Voir sur la carte
Archivé · expiré 5 years ago

Danger d’avalanche

Mon
Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Various hazards are present out there; from hard wind slabs to thin breakable crust. Adapt your trip and your objective to remain safe all weekend.

Problèmes avalancheux

  • Wind Slabs

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

    Exposed slopes at higher elevations may harbour wind slabs that could be reactive in exposed areas. While these slabs may be thin, they could be poorly bonded to the underlying snow, so be extra cautious in lee terrain and convex rolls.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3.5

    A persistent slab problem formed by a crust down 100-270 cm has created a low likelihood, high consequence scenario that is difficult to forecast. There has been an increase of avalanche reports on this layer recently. Although there was evidence of recent large avalanches on the layer, it is uncertain how the warm temperatures have affected the snowpack. Avoid likely trigger spots such as steep, rocky slopes with a shallow or thin to thick snowpack. Additional loads like small avalanches can trigger deeper weak layers. The same feature or path can slide repeatedly when the persistent weak layer is reloaded with new snow. 

Confidence

High - Confidence is due to a stable weather pattern with little change expected.

Weather Forecast

FRIDAY NIGHT: Cloudy with flurries, moderate southwesterly wind, treeline temperatures around -3 C, freezing level around 1000 m.

SATURDAY: Mostly cloudy, up to 5 cm new snow, moderate to strong southwesterly wind, treeline high around -3 C, freezing level around 1600 m.

SUNDAY: A mix of sun and clouds, moderate westerly wind increasing to extreme, treeline high around -6 C,freezing level at valley bottom rising to 1000 by midday.

MONDAY: Cloudy, no precipitation, treeline high around -3 C, strong southwesterly wind, freezing level around 1500 m.

Avalanche Summary

Three very large avalanches were reported from this region on Thursday. The avalanches appear to have failed on the early December crust and showed wide propagation. They occurred on southwest to southeast aspects and were naturally triggered in response to rising temperatures and solar radiation.

These avalanches follow a previous sporadic pattern of very large avalanches that have been reported from this region and neighbouring regions over the last couple of weeks. 

Snowpack Summary

A breakable crust is now capping the 15 cm of recent snow which is settling fast and has become moist due to past warm temperatures. This crust seems thinner on north and east slopes but observed up to 1800 m. This snow sits on a variety of old surfaces, including soft snow in sheltered areas and wind slabs in exposed and open areas which formed over the past few days.

The most notable layer of concern in the snowpack is a crust that was formed in early December and is now down 100-270 cm. This layer appeared to have "waken up" in response to warm temperatures and solar radiation on Thursday Jan 13, when at least three very large avalanches were reported on this layer. This layer has created a low likelihood, high consequence scenario which is best managed through conservative terrain choices and disciplined backcountry travel techniques.

Terrain and Travel

  • Avoid freshly wind loaded terrain features.
  • Be alert to conditions that change with elevation and wind exposure.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.

Régions couvertes