Bulletin d’avalanche

Northwest Coastal

Dec 19 – 20, 2017Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Thu
Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Cool and stable weather should mean a gradually strengthening snowpack.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    20 to 60cm of snow fell during the weekend with wind from the SW, W, NW and SE. As a result, wind slabs on a wide variety of aspects should be expected.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3
    As recently as this weekend, large avalanches ran on deep persistent weak layers near the base of the snowpack. While it appears to be more likely in the north of the region, the possibility of triggering something big should remain on your radar.

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

Wednesday: Dry with some clear spells until late in the day. Strong northwesterly winds. Models indicate an inversion will set up for Wednesday afternoon with valley temps around -10C and above-zero between 1400m and 2000m. Thursday: Light snow, 2-5 cm expected, clearing thorough the day. Winds initially strong northwesterly but diminishing through the day. Treeline temps around -8C. Friday: Cold and dry. Moderate and locally strong easterly winds. Treeline temps around -12C.

Avalanche Summary

The north part of the region reported up to size three natural avalanches over the weekend. Poor visibility limited observations in the south but no new avalanches were reported.

Snowpack Summary

The region picked up 20 to 60cm of storm snow over the weekend accompanied by winds out of the southwest, west, northwest, and most recently the east. This will have set up storm slabs in more sheltered areas and wind slabs on a wide variety of aspects in more exposed areas. These new storm and wind slabs may rest on a melt freeze crust (reported to be 3 to 15cm thick), and there are reports there also may be surface hoar resting above this crust in sheltered locations. Below this crust the mid-pack is reported to be generally strong. You can expect to find a second prominent crust, which was buried at the end of October, 100 to 200cm below the surface. This lower layer may have associated facets, particularly in more shallow locations.

Régions couvertes