Bollettino valanghe

North Columbia

Jan 27, 2018Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 9 years ago

Pericolo valanghe

Sun
Mon
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Tricky conditions with a slowly increasing load over multiple weak layers in the snowpack. Take a conservative approach to your terrain choices.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–4
    Several weak layers are buried in the snowpack, creating very large avalanches when triggered.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–3
    Recent snow and wind have built slabs that can be triggered by the weight of a person. A storm slab could step down to a deeper weak layer, creating a surprisingly large avalanche.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

Saturday: 5-10 cm snow. Light to moderate south-easterly winds. Alpine temperature near -10. Sunday: 5-10 cm snow. Moderate south-westerly winds. Alpine temperature near -7.Monday: 10-15 cm snow. Moderate to strong south-westerly winds. Alpine temperature near -1.More information can be found in the Mountain Weather Forecast.

Avalanche Summary

A widespread natural avalanche cycle was observed on Wednesday, with a few more occurrences on Thursday. Avalanches were storm slabs (up to size 2.5) and persistent slabs (up to size 4), running on all aspects and elevations. Although the natural avalanche cycle is diminishing, human triggering will remain likely and avalanches could be surprisingly large due to the structure of the snowpack.

Snowpack Summary

The current snowpack is complex, with three active weak layers that we are monitoring.60-90 cm of storm snow sits on a crust and/or surface hoar layer from mid-January. The crust is reportedly widespread, with the possible exception of high elevation north aspects. The mid-January surface hoar is 5 to 20 mm in size and was reported at treeline elevations and possibly higher. The recent storm snow fell with strong south winds, producing wind slabs in lee features at treeline and alpine elevations and in open areas below treeline.Deeper in the snowpack, the early-January persistent weak layer is 80 to 100 cm below the surface. It is composed of surface hoar on sheltered slopes as well as sun crust on steep solar aspects and is found at all elevation bands. Snowpack tests show sudden fracture characters and signs of instability such as whumpfs, cracking and avalanches. Another weak layer buried mid-December consisting of a facet/surface hoar/crust combination is buried 100 to 150 cm deep. It is most problematic at and below tree line. A rain crust buried in November is generally 150 to 200 cm deep.

Regioni coperte