Lawinenlagebericht

Northwest Inland

Feb 24 – 25, 2022Avalanche Canada
Auf der Karte ansehen
Archiviert · abgelaufen 5 years ago

Lawinengefahr

Sat
Sun
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
Vollständige Karte öffnen

Kernpunkte

Use caution around ridge crests, convex rolls, and steep slopes on all aspects. Signs of windslab instability may be hidden by new snow. Snowfall varied across the region on wednesday.

Lawinenprobleme

  • Storm Slabs

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

    Up to 20 cm of new snow fell on wednesday (with the highest amounts around Smithers and west from there). Small, reactive storm slabs were being triggered in some locations.

    The new snow fell with mostly light winds, but it may bury windslabs that were bonding poorly to the underlying crust. Soft, unconsolidated surface snow may hide signs of windslab instability, so you may have to dig down for more information. Decision making can be tricky in this situation, so it might not be the time to choose a committing line.

    Recent wind direction has varied from southwest through northeast. Buried wind slabs may be found on atypical aspects and features due to reverse-loading. Slabs have been reactive and sliding surprisingly far on the underlying crust. The most likely place to trigger a wind slab is near ridge crest and on convex terrain features, where the slope rolls away from you.

Confidence

Moderate - The snowpack structure is generally well understood. Recent weather patterns have resulted in a high degree of snowpack variability within the region.

Weather Forecast

Wednesday Night: Clear. No new snow expected. Light north wind. Alpine low around -10 °C.

Thursday: Sunny. No new snow expected. Light to moderate northwest ridgetop wind. Alpine high around -6 °C.

Friday: Sunny with scattered cloud. No new snow expected. Moderate southwest ridgetop wind. Possible temperature inversion could make for temperatures above -5 °C above 1500 m.

Saturday: Mostly cloudy. 2-5 cm of snow expected. Strong south ridgetop wind, trending to extreme at higher elevations. Temperature inversion breaking down. Alpine high around -7 °C.

Avalanche Summary

On Wednesday, an AST course reported some natural windslab avalanches to size 1.5 in steep alpine features, as well as several, size 1 natural loose dry avalanches, and rider triggered slab avalanches. For more info, see their Mountain Information Network post here.  

On Tuesday, a professional operation northeast of Hazleton reported a couple of natural avalanches up to size 2.5 that may have occurred on Monday. They were on north or northeast aspects around treeline, and one was a windslab, while the other was a cornice failure that likely triggered a windslab avalanche on the slope below. 

On Monday, avalanche activity was limited to thin, size 1 wind slabs and loose dry sluffing.

Several skier triggered wind slabs size 1-1.5 have been reported over the past few days, most in predictably wind loaded lees or convexities, near ridgetop, around treeline or higher. On Saturday near Kispiox, a size 1.5 was accidentally triggered on a previously skied slope and ran surprisingly far on the underlying crust.

Snowpack Summary

On Wednesday, up to 20 cm of new snow fell with mostly light winds. This new snow overlies a variety of old, generally wind-affected surfaces.

this new snow overlies variable wind effect at upper elevations, and exposed windward features that were previously scoured down to the crust in some areas in the Babines. 

20-50 cm from the snow surface is a 10-20 cm thick rain crust which effectively caps the underlying snowpack, making human triggering of avalanches on weak layers deeper in the snowpack unlikely, but this crust has been breaking down in some locations, with faceting observed above and below it. Large loads like big chunks of falling cornice may now be able to trigger weak layers below the crust.

Terrain and Travel

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
  • Recent new snow may be hiding windslabs that were easily visible before the snow fell.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.

Abgedeckte Regionen