Bollettino valanghe

Lizard-Flathead

Feb 22 – 23, 2017Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 10 years ago

Pericolo valanghe

Thu
Fri
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Apri la mappa completa

In sintesi

Natural deep persistent slab avalanches size 3.0 have been reported in this region.

Problemi valanghivi

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–3
    Fresh cornice growth may be large and fragile. Cornice falls may release storm slabs, or step down to deeply buried weak layers resulting in large avalanches.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–3
    Deep storm slabs (50-60cm) may take some time to settle and bond to the old surface. This problem may linger in areas with a hard rain crust below the storm snow.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–4
    There have been two natural deep persistent slab releases in the past two days in the Lizard range. Both of these avalanches were on northeast aspects in the alpine, and released to size 3.0 or larger.

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

Tonight: Overcast with a chance of 3-5 cm of new snow combined with light northwest winds and freezing to valley bottoms. Thursday: Broken skies with light variable winds and -15 in the alpine. Friday: Mix of sun and cloud with light variable winds and -15 in the alpine. Saturday: Mostly sunny with moderate northwest winds and alpine temperatures close to -20.

Avalanche Summary

There was a report on Tuesday of a natural avalanche size 3.5 on Mt Hosmer on an East aspect at 2100 metres that appears to have released on or stepped down to the weak deep persistent layer of sugary facets near the ground. On Wednesday we had a report of a size 3.0 avalanche on "Big Steep Mother" bowl on a northeast aspect at 2100 metres in the alpine in the Lizard range. This avalanche appears to have been started by a cornice fall that released a storm slab that then "stepped down" to deeply buried weak facets. Explosives control on Wednesday resulted in cornice falls up to size 2.5, and storm slabs with some pockets of un-supported terrain stepping down to size 2.5. All avalanches reported were from north-northeast aspects.

Snowpack Summary

There is now 50-60 cm of storm snow that is expected to settle into a storm slab. This slab sits above a thick rain crust below 1900 m and a generally well settled snowpack. Isolated basal weaknesses may still exist in shallow snowpack areas. These weak areas appear to be on north-northeast aspects in the alpine. If the winds shift direction over the next few days, watch for new wind loading on south-west aspects.

Regioni coperte