Boletín de aludes

Vancouver Island

Mar 4 – 5, 2023Avalanche Canada
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Archivado · caducó 4 years ago

Peligro de aludes

Mon
Tue
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Lo esencial

Mountain ranges on the southern half of the island are forecast to see enhanced snowfall amounts Saturday. If you see more than 25 cm of new snow, treat avalanche danger as HIGH in the alpine. Stick to conservative terrain and watch for signs of instability like shooting cracks, whumfing and recent avalanches.

Problemas de aludes

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2

    Fresh storm slabs will form in areas that see significant snowfall Friday night and Saturday. Elsewhere, previous storm slabs may remain reactive to rider triggers in wind loaded terrain features at upper elevations. At lower elevations, new snow gains cohesion and slab property as it settles amid mild temperatures.

    On the north island, there may remain potential for slabs to fail down to a recently buried crust, propagate widely and run surprisingly far.

Confidence

Low

Avalanche Summary

With poor visibility through the storm(s), avalanche observations have been limited to loose dry avalanches up to size 2 observed at various elevations by our field team on Thursday.

A slew of MINs from the Mt Cain area last weekend reported several rider triggered storm/wind slab avalanches up to size 2. We suspect they were running on a recently buried crust.

If you head into the backcountry please consider sharing your observations on the Mountain Information Network!

Snowpack Summary

New and recent snow is being loaded into lee terrain features by moderate wind at upper elevations, while remaining soft in sheltered areas.

A thick, widespread crust formed in mid February sits 40-80 cm deep. Near Mt Cain, the crust is glassy with faceted crystals sitting ontop of it, which makes for a poor bond to the overlying slab of snow. For more details, check out this reel from our field team. Elsewhere the crust seems to be bonding well. You can check the bond in your local area by performing a simple hand shear test on an isolated block.

The mid and lower snowpack is well consolidated, containing a series of well-bonded crusts.

Weather Summary

A slow-moving low slides southward over the island, producing enhanced upslope snowfall on the west coast Friday night, wrapping around to impact the eastern ranges of the southern half of the island on Saturday with hot spots in the Strathcona and Cowichan ranges. Flurries continue into the week as the low slips south of the border and lingers offshore of Washington.

Friday

5-10 cm of new snow in most areas, up to 30 cm in the Clayoquot area. Moderate southwest wind. Alpine high -5 ºC.

Saturday

5-10 cm in most areas, up to 30 cm in the eastern ranges including Strathcona and Cowichan. Moderate to strong southeast wind. Alpine high -4 ºC.

Sunday

5-10 cm in most areas. Southeast wind easing to light. Alpine high -3 ºC.

Monday

5-20 cm overnight then clearing to a mix of sun and cloud. Light southeast wind. Alpine high -2 ºC. Freezing level 1000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Dial back your terrain choices if you are seeing more than 25cm of new snow.
  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • As the storm slab problem gets trickier, the easy solution is to choose more conservative terrain.
  • Seek out sheltered terrain where new snow hasn't been wind-affected.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.

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