Boletín de aludes

Yukon

Mar 29 – 30, 2023Avalanche Canada
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Archivado · caducó 4 years ago

Peligro de aludes

Fri
Sat
Alta montaña
1 · Débil
Límite del bosque
1 · Débil
Bajo el límite
Sin grado
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Lo esencial

Watch for unstable snow on isolated terrain features. Although triggering slabs on deeply buried weak layers is unlikely under the current conditions, we'll be avoiding rocky start zones and thick to thin transitions for the remainder of the season.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely - Possible
    Tamaño
    2–3

    A weak layer of surface hoar and/or faceted grains around a hard crust sit in the mid snowpack. This layer is buried around 80 cm in the eastern portions of the region and up to 200 cm around White Pass and Haines Pass.

    This layer has previously produced widely propagating avalanches in alpine terrain and it is capable of being remotely triggered from a distance. The most likely area for riders to trigger it is in wind-sheltered, north-facing terrain, and in rocky terrain where the snowpack is thin.

Confidence

High

Avalanche Summary

White Pass: Over the weekend, small (size 1) rider-triggered wind slabs were reported in the alpine. A natural loose wet avalanche cycle up to size 2 occurred on steep south aspects around treeline on Friday.

Haines Pass: On Monday, a couple of large, deep avalanches were observed in the alpine. A size 3 on a northeast aspect was thought to have run during a wind event on Sunday, and a size 2.5 on a south aspect was thought to have been triggered by strong sun. These have been isolated occurrences so far but may be a sign of things to come as the spring warms up.

If you head out in the backcountry, let us know what you are seeing by submitting a report to the Mountain Information Network.

Snowpack Summary

Generally, surfaces are wind-pressed in the alpine and crusty on solar aspects especially around treeline. Soft snow may be found in shady, wind-sheltered areas. At Haines Pass, 5-10 cm of snow sits over a rain crust below 1300 m.

Weaknesses in the mid and lower snowpack are unlikely to produce avalanches under the current conditions. A weak layer of surface hoar/crust/facets buried in early January is now over 1 m deep in most areas, and has not produced avalanche activity for several weeks. The lower snowpack consists of basal facets, particularly in thin snowpack areas.

Weather Summary

Wednesday night

Increasing cloud. Light to moderate southwest wind. Alpine low -8 °C.

Thursday

Cloudy with flurries bringing a trace of snow. Moderate southwest wind. Alpine high -6 °C.

Friday

3-8 cm of new snow. Moderate southwest wind. Alpine high -5 °C.

Saturday

A trace of new snow. Light southeast wind. Alpine high -5 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
  • Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

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