Boletín de aludes

Glacier

Jan 21 – 22, 2023Avalanche Canada
Ver en el mapa
Archivado · caducó 4 years ago

Peligro de aludes

Mon
Tue
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado

Lo esencial

New snow and wind will continue to add to the load over the early January surface hoar layer. Be extra cautious in windloaded lee terrain, where this layer may be getting buried deeply enough to produce large avalanches.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–2.5

    Expect renewed reactivity as wind and new snow continue to add to the load on the Jan 3 surface hoar (5-10mm). This layer is buried ~40cm and will be most reactive at ridgeline or in open lee features, where wind has stiffened the surface. If triggered, this slab has the potential to step down to the deep persistent layer.

  • Deep Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely - Possible
    Tamaño
    2–4

    The Nov 17 layer, which consists of a faceted crust and decomposing surface hoar, highlights a weak basal snowpack. Be particularly cautious in steep, rocky areas with thin snow coverage, where the majority of the snowpack is weak and faceted.

Confidence

Moderate

Avalanche Summary

On Friday, we received a report of a skier triggered size 1.5 windslab at the entrance to Nicky's notch.

On Thursday, there was a report of a size 1 skier triggered slab avalanche near the Dome Col, which was was suspected to have failed on one of the surface hoar layers in the upper snowpack.

On Wednesday, a field team today triggered a couple of size 1.0 slab avalanches on small convex rolls at treeline - one of these failed on the Jan 3rd surface hoar layer down 35cm. There was also a MIN report of a skier triggering a similar size 1.0 slab on the Jan 3rd layer on McGill shoulder.

In neighboring areas there are continued reports of isolated human triggering of the recently buried surface hoar layers, as well as natural/explosive triggering of the deep persistent facet layer.

Snowpack Summary

New snow and wind will continue to build the slab over the early January surface hoar layers. These two surface hoar (SH) layers, present in the upper 40cm, have been reactive to human triggering recently.

Recent warm temperatures have left a melt-freeze crust at or near the surface below ~1600m.

The mid-pack facets are slowly rounding and gaining strength, while the basal facets and Nov 17 facet/SH/crust weakness are still reactive when isolated in snowpack tests.

Weather Summary

We're going to get a minor blip of snow (up to 10cm) and gusty SW winds on Saturday, with the passage of a cold front. After that ground hog day continues well into next week, with the same old mixed bag of mostly cloudy skies, isolated flurries, seasonal temps (-10 to -15*C) and light winds.

Terrain and Travel Advice

  • Be especially cautious as you transition into wind affected terrain.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

Regiones cubiertas