Lawinenlagebericht

Northwest Coastal

Mar 1 – 2, 2022Avalanche Canada
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Archiviert · abgelaufen 5 years ago

Lawinengefahr

Thu
Fri
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering

Kernpunkte

Moderate amounts of new snow and wind will form wind slabs on Monday. Be cautious as you drop into lines or high-mark and back off if you experience stiff surface snow or cracking.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible - Likely
    Größe
    1–2

    Variable winds on Monday will deposit new snow into reactive wind slabs in upper treeline and alpine leeward features. Old wind slabs still exist so be suspicious of the presence of wind slab in any break-over in terrain. 

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Monday night: Mostly cloudy. Up to 10cm of new snow. Light winds from the southwest. -4°C.

Tuesday: Mostly cloudy. Up to 10cm of new snow. Moderate winds from the southwest through southeast. A low of -4°C and a high of -1°C. 

Wednesday: Mostly cloudy. Up to 10cm of snow at higher elevations and small amounts of rain in the valleys. Winds light from the south. A low of -2°C and a high of +2°C.

Thursday: A mix of sun and cloud. Winds light and variable. No new precipitation. A low of -3°C and a high of +2°C.

Avalanche Summary

On Sunday, a professional operation northeast of Terrace reported several, small, natural windslab avalanches that occurred over the weekend. They were on steep, convex, lee features at treeline.

On Saturday, professional operations across the region reported several small, rider triggered windslab avalanches, failing on feathery surface hoar crystals, or on firm, wind effected surfaces. 

Snowpack Summary

New snow on Monday will be deposited into wind slabs by variable winds on immediate leeward features. Some of these wind slabs are being deposited on weak, feathery surface hoar crystals in more sheltered areas and could produce larger avalanches. 

New snow appears to be bonding to a rain crust buried in mid-February, but we are not ready to completely trust that bond until it has weathered some significant warming or precipitation. 

Depth of the rain crust is quite variable across the region, from 20-100 cm, and can even be found on the surface in very wind exposed terrain. This obvious, 10-30 cm thick crust effectively caps the underlying snowpack, making human triggering of avalanches on deeper weak layers unlikely.

Terrain and Travel

  • Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
  • Highmark or enter your line well below ridge crests to avoid wind loaded pillows.
  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.

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