Lawinenlagebericht

Northwest Inland

Apr 5 – 6, 2021Avalanche Canada
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Archiviert · abgelaufen 5 years ago

Lawinengefahr

Wed
Thu
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering

Kernpunkte

Watch for cornices and reactive slabs near ridgetops and lee terrain. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Up to 15 cm fresh snow collecting in upslope areas will be deepest and most reactive where impacted by wind. Use caution around ridges and lee features, and when transitioning into wind affected terrain.

  • Cornices

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–2.5

    Cornices are large and looming along many ridgelines, and have likely grown with the recent wind.

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

MONDAY NIGHT: Flurries, up to 5 cm, moderate southwest wind, treeline temperatures around -5 C with freezing levels dropping below 500 m.

TUESDAY: Scattered flurries with up to 15 cm of new snow accumulating by the end of Tuesday, moderate southwest wind, treeline temperatures up to -1 C with freezing level up to 900 m.

WEDNESDAY: Mix of sun and cloud with some light flurries, light west wind, treeline temperatures around -4 C and freezing level dropping to valley bottom.

THURSDAY: Flurries arriving late in the day, increasing southwesterly wind, treeline temperatures below -3 C with freezing level at valley bottom.

Avalanche Summary

Strong winds contributed to intense wind-loading in areas on Sunday with fresh wind slab avalanches to size 2 failing in immediate lee features.

Reports from Saturday included a few isolated avalanches with some size 1-2 cornice failures, one size 2 wind slab on a southeast aspect, and one size 2 wet loose avalanches on a south-facing slope.

Snowpack Summary

Wind slabs formed by light amounts of recent snow and southwesterly winds may linger below alpine ridgetops. A firm crust exists at lower elevations. Cornices are large and looming at this time of year.

Buried 70-120 cm. deep, a spotty layer of surface hoar may exist on sheltered north aspects, but no recent avalanches have been reported on this layer. 

The lower snowpack is reported as well settled and strong in most areas. However, weak facets exist at the base of the snowpack in the more shallow snowpack zones within much of the region and have the potential to be triggered on steep, rocky slopes with a shallow or thin to thick snowpack; especially with large loads such as a cornice fall.

Terrain and Travel

  • Be careful as you transition into wind affected terrain.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Avoid exposure to slopes that have cornices overhead.
  • Dial back your terrain choices if you are seeing more than 20 cm of new snow.

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