Boletín de aludes

South Rockies

Mar 4 – 5, 2022Avalanche Canada
Ver en el mapa
Archivado · caducó 5 years ago

Peligro de aludes

Sun
Mon
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
Abrir el mapa completo

Lo esencial

Choose simple terrain, and avoid exposing yourself to terrain traps. Stormy conditions continue, and the snowpack is still adjusting to the new load.

Problemas de aludes

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2.5

    Continued loading from new snow and wind has formed storm slabs on all aspects. These have been especially reactive where slabs sit on top of crusts or cold sugary crystals.

    Continue to make conservative choices and give the storm snow time to settle and stabilize.

    Moderate to strong southwest winds are loading lee slopes around ridge crests, as well as cross-loaded features making these more likely places to trigger an avalanche.

Confidence

Moderate - Forecast precipitation (either snow or rain) amounts are uncertain. Uncertainty is due to difficult to forecast freezing levels. The snowpack structure is generally well understood.

Weather Forecast

There is some upslope snowfall enhancement possible for the South Rockies into Thursday night. Possible periods of localized heavy snowfall due to convection. 

Thursday Night: Cloudy. 5-15 cm of snow expected. Light west ridgetop wind, trending to moderate at higher elevations. Treeline low around -8 °C.

Friday: Mostly cloudy. 2-5 cm of snow expected. Light variable wind. Treeline high around -7 °C.

Saturday: Mix of sun and cloud. Possible trace of snow expected. Light variable ridgetop wind, trending to strong north at higher elevations. Treeline high around -7 °C.

Sunday: Mix of sun and cloud. 0-3 cm of snow expected. Light northwest ridgetop wind, trending to moderate north at higher elevations. Treeline high around -6 °C.

Avalanche Summary

On Thursday, small, loose dry avalanches were reported in the recent storm snow. Also, south of Crowsnest Pass, one size 2 explosive controlled avalanche was reported, starting as a storm slab, and getting larger as it entrained loose new snow lower on the slope.

On Wednesday there was more evidence of a large avalanche cycle from size 2-3 in the region. The field team also experienced whumpfing at treeline elevations in the Elkford area.

A large (size 2.5) avalanche was remotely triggered from a ridge in a neighboring forecast region as well.  

Snowpack Summary

Convective flurries could bring up to 25 cm of new snow overnight Thursday and through Friday. If these localized cells of precip miss your area, you could get none:(

Snowfall amounts have varied substantially since the start of the week with south of highway 3 receiving 30-50 cm and the north getting 10-20 cm. This fell as rain at lower elevations. Wind loading from moderate to strong southwest wind redistributed the recent storm snow, but winds are now light and should be moving less snow. 

The recent storm snow still needs time to bond to a variety of old surfaces such as firm wind-pressed snow, sun crust on solar aspects, and potentially weak, sugary crystals.

The middle and lower snowpack are generally well consolidated, with a crust/facet layer from early December found near the bottom of the snowpack. It is currently considered dormant but could become active later this season. 

Terrain and Travel

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Start with simple terrain and gather information before thinking about more committing features.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.

Regiones cubiertas