Bollettino valanghe

Yukon

Apr 25 – 26, 2023Avalanche Canada
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Archiviato · scaduto 3 years ago

Pericolo valanghe

Thu
Fri
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
Senza grado

In sintesi

Forecast 10-15 cm of snow and moderate southerly wind may form reactive wind slabs on lee features in specific locations.

Concern for triggering very large deep persistent slab avalanches in the Haines Pass area remains. Avoid steep, rocky, and wind-affected areas where triggering slabs are more likely.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–2.5

    Forecast 10-15 cm of snow and moderate southerly wind may form reactive wind slabs on lee features in specific locations.

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    Cornices are very large and loom over slopes below like gargoyles. Cornice falls may trigger large avalanches on the slopes below.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2–3.5

    A weak layer of crust/facets down 100+ cm and/or weak facets at the bottom of the snowpack have recently become reactive.

    Snowpack and avalanche observation data are currently very limited in this region which makes this kind of avalanche problem very difficult to forecast.

Confidence

Low

Avalanche Summary

No avalanches were reported on Monday. However, observations in this region are currently very limited.

Observations are limited at this time of year, please consider sharing any information or photos you have on the Mountain Information Network to help guide our forecasts.

Snowpack Summary

Forecast 10-15 cm of snow and moderate southerly wind may form reactive wind slabs on lee features in specific locations.

Cornices are very large and loom over slopes below like gargoyles. Cornice falls may trigger large avalanches on the slopes below.

A robust crust exists on all aspects up to approximately 1400 m and to ridgetop on sunny aspects.

A weak layer of surface hoar/crust/facets buried in early January is now around 100 cm down in most areas. A significant warming event or a large trigger (like a falling cornice) are the most likely things to activate this layer.

Weather Summary

Tuesday Night

Cloudy with isolated flurries; 0-5 cm / 40 km/h southeast ridgetop wind / Temperature at treeline around -5 C / Freezing level valley bottom

Wednesday

Cloudy with flurries; 5-15 cm / 35 km/h south ridgetop wind / Temperature at treeline around 1 C / Freezing level 1100 m

Thursday

Mostly cloudy with isolated flurries; 5-10 cm / 60 km/h south ridgetop wind / Temperature at treeline around 1 C / Freezing level 1100 m

Friday

Cloudy / 30 km/h south ridgetop wind / Temperature at treeline around 2 C / Freezing level 1300 m

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Wind slabs may be poorly bonded to the underlying crust.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
  • Cornice failure may trigger large avalanches.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Regioni coperte