Bulletin d’avalanche

Long Range Mountains

Feb 17 – 18, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Sun
Mon
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
Sans niveau
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Points saillants

Watch for small pockets of reactive wind slab forming on south facing terrain features. Expect more reactivity where new snow sits over a crust.

As usual look to sheltered areas to avoid wind slabs and find better riding conditions.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Northerly winds will build small pockets of wind slab where loose snow is available for transport (think areas unaffected by Wednesday's rain, and where there is fresh snowfall).

    Where wind loading sits over a crust, expect slabs to be smaller but possibly more reactive. Where the crust is not present, loading will build over older and larger wind slabs that are more stubborn to rider triggers, likely found on many aspects.

Confidence

Moderate

Avalanche Summary

Slab avalanches have been reported over the last week, in wind affected terrain. These were naturally triggered and ranged from size 1-2.5. Check out these MINS for more details: near Glenburnie, Gros Morne, Western Brook Gorge.

Snowpack Summary

By Saturday morning up to 10 cm of fresh snow can be found, likely redistributed into deposits on south facing slopes by northerly winds. This snow will fall over dense wind affected snow at higher elevations, and over a melt freeze crust at lower elevations formed by light rain on Wednesday. This crust is variable throughout the region (likely more prominent in the south) and may form a good bed surface for avalanche activity. Highly variable amounts of wind affected snow make up the rest of the upper snowpack.

A hard melt freeze crust sits in the middle to lower snowpack. Depending on wind loading and location, this crust is anywhere from 10 cm to over 100cm deep. A weaker layer of faceting crystals sits immediately above this crust. Reports suggest this interface is bonding well however larger avalanches are still possible to 'step down' to this layer where a weaker bond exists, more likely in shallow snowpack areas. The snowpack below this crust is dense and well bonded from previous rainfall.

Weather Summary

Friday Night

Snow overnight, with 5-10 cm favouring the south. Skies remain cloudy with northerly winds around 30 km/hr.

Saturday

A mix of sun and cloud with flurries of snow possible. High temperatures of -12 °C. North-northwest winds 30 km/hr.

Sunday

Mostly cloudy with flurries possible bringing up to 3 cm. Squalls are possible, delivering up to 10 cm locally. Winds 50km/hr from the west. High temperatures around -10 °C.

Monday

Cloudy with light snow beginning late in the day, around 5 cm. Freezing levels rise gradually over the day, reaching 500 m by midday. Strong southerly winds reach 120 km/hr.

Overnight freezing levels rise above 1000 m and snow will turn to rain. Widespread 15-30 mm is expected with up to 50 mm possible in the south.

Tuesday

Freezing levels rapidly fall back to valley bottom over the morning. Winds shift to 50 km/hr westerly. Flurries are possible.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Be especially cautious as you transition into wind affected terrain.

Régions couvertes