Bollettino valanghe

Lizard-Flathead

Mar 16 – 18, 2020Avalanche Canada
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Archiviato · scaduto 7 years ago

Pericolo valanghe

Wed
Thu
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole

In sintesi

Lingering wind slabs below ridgetops may remain reactive to human triggers. Strong solar radiation weakens cornices and often causes them to fall onto slopes and trigger large avalanches. Pay attention to what's above your head if the sun is out.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Strong easterly winds have drifted the 10-20 cm of new snow into wind slabs on lee terrain features in a reverse loading pattern. These wind slabs may be possible to human trigger. Cornices may also be reaching their breaking point.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–1.5

    Rising temperatures and intense solar radiation may initiate wet loose avalanches and weaken cornices. Minimize exposure to steep, sun-exposed slopes and cornices.

Confidence

High - Confidence is due to a stable weather pattern with little change expected.

Weather Forecast

Monday night: Clear, Moderate west winds, alpine low -13 C, freezing level valley bottom.

Tuesday: Sunny, light northeast winds, alpine high 2 C, freezing level 1600 m.

Wednesday: Sunny, light to moderate northwest winds, alpine high -3 C, freezing level valley bottom.

Thursday: Sunny, light west winds, alpine high -6 C, freezing level valley bottom.

Avalanche Summary

Check out this MIN of a notable avalanche reported on Monday.

Several large (size 2) wind slabs were reported on Saturday releasing naturally on lee slopes above 1700 m. 

Snowpack Summary

Strong easterly winds have drifted recent snow into wind slabs on lee terrain features in a reverse-loading pattern. 

A total of 30 to 60 cm of snow from the previous storm has been redistributed by wind or is well-settled. This snow sits over another layer of buried wind slabs in exposed areas and a sun crust on solar aspects (south through west facing slopes). Melt-freeze crusts extend up to 1900 m on other aspects. 

A thick crust/facet layer currently sits 30-60 cm below the surface. There has been only one avalanche reported on this layer since February 17th. The middle of the snowpack is generally strong, but the base of the snowpack contains weak basal facets that are most prominent in shallow rocky start zones.

Terrain and Travel

  • Stay off recently wind loaded slopes until they have had a chance to stabilize.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

Regioni coperte