Lawinenlagebericht

Northwest Coastal

Feb 17 – 18, 2020Avalanche Canada
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Archiviert · abgelaufen 7 years ago

Lawinengefahr

Wed
Thu
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

Start small and ease your way into terrain this week. Be cautious around deep wind loaded pockets in wind exposed elevations, as well as in sheltered areas where recent storm snow may sit on weak layers.

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible - Likely
    Größe
    1–2.5

    40-60 cm of new snow has accumulated over the past week. In many areas the new snow will be on a positive stabilizing trend, but human triggered avalanches remain a serious concern around steep slopes where the new snow is settling over crust or surface hoar layers as well as in exposed areas where much of this snow has been transported into thick and reactive wind slabs.

Weather Forecast

Sunday night: Mainly cloudy with scattered flurries. Moderate northwest winds. Freezing level valley bottom.

Monday: Cloudy with sunny periods. Moderate southwest winds easing to light. Freezing level 800 m.

Tuesday: Mix of sun and cloud. Light southwest winds. Freezing level 600 m.

Wednesday: Mix of sun and cloud. Southwest winds building to strong. Freezing level 600 m.

Confidence

High -

Avalanche Summary

Reports from Saturday include: natural wind slab avalanches size 2-2.5 observed in the alpine above highway corridors; and skier triggered storm slabs size 1-1.5 running on surface hoar 40 cm deep.

Looking forward, natural avalanche activity is expected to decline while the likelihood of human triggered avalanches persists a bit longer. Wind loaded features at higher elevations are primary concerns, however storm slab triggering on steeper slopes in sheltered areas isn't yet out of the question, particularly where recent snow overlies crust or surface hoar.

Snowpack Summary

20-30 cm of new snow accumulated in the region over Friday night and Saturday, bringing snow totals for this week to about 50-80 cm. With settlement, this total is likely closer to 40-60 cm. This snow sits on a variety of surfaces including wind-affected snow (high elevation/exposed areas), melt-freeze crust (lower elevations), sun crust (sun-exposed slopes), faceted snow and/or surface hoar (shaded aspects).

A thin layer of facets that formed during the January cold snap is now about 120-170 cm below the surface while an early season crust lingers at the base of the snowpack. These layers produced a few large natural avalanches in early February but have more recently been nonreactive.

Terrain and Travel

  • Avoid freshly wind loaded terrain features.
  • Approach steep, open and/or sparsely treed slopes cautiously.
  • Be alert to conditions that change with elevation and wind exposure.

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