Bollettino valanghe

Banff Yoho Kootenay

Apr 7 – 8, 2019Parks Canada
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Archiviato · scaduto 7 years ago

Pericolo valanghe

Tue
Wed
Alta quota
Senza grado
Limite del bosco
Senza grado
Sotto il limite
Senza grado
Apri la mappa completa

In sintesi

Recent snow and wind has created fresh windslabs in many leeward alpine locations. Take note that many small slabs were observed in steep couloirs on Saturday.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–1.5
    A period of strong wind overnight on Saturday has created slabs in lee features in the alpine. Of note, evidence of these slabs was observed at the base of cones that are situated below couloirs. The windslabs were small in size (max size 1).

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    1–2
    A hard slab sitting over weak facets up to 60cm down remains a concern where found: mainly on N aspects in the alpine. We have seen a few human triggered avalanches in steep, isolated features such as moraines and glacier rolls over the past week.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    1–1.5
    The new snow will react notably with localized solar input, so position yourself away from steep features while the sun is beating down. This is particularly relevant at higher elevation where recent snowfall amounts are greater. 

Weather Forecast

A clear-ish morning will be followed by increasing cloud and light precipitation. Light precip will continue until late on Wednesday when a front will deposit up to 15cm of new snow. Throughout the period, temperatures at the valley bottom will be just above zero.  Wind will remain in the Mod/Strong (West) range through tonight and then dissipate.

Snowpack Summary

Up to 15cm recent snow at upper elevations. Melt-freeze crusts are common. On North and East aspects in the alpine, up to 30cm of unconsolidated snow can be found. Below this, a stiff slab overlying weak facets remains a concern in some places and a weak, faceted snowpack, remains a concern in thin areas.

Avalanche Summary

On a flight to the Wapta Icefields and through the Lake Louise group, forecasters observed several size 1 windslabs. These were typically on North aspects on alpine features, and often were observed having pulled out at the top of fans (bottoms of couloirs). While risk of burial is low, the risk of being carried to an undesirable location is there.

Confidence

Regioni coperte