Bulletin d’avalanche

South Coast Inland

Jan 4, 2018Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

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

The odd small wind slab may still be human triggerable in more extreme terrain. The picture should start to change on Saturday as storm snow returns to the South Coast.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–2
    Aided by time and warmth, the storm snow has settled into a stubborn old slab. For the most part, this slab is bonding well to the underlying surface but there may still be a wind slab issue in more extreme terrain.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

The weather pattern is changing, albeit slowly. As the ridge shifts east, a trough pattern on the west coast begins to bring cloud and precipitation beginning Thursday.THURSDAY: A few clouds in the morning with cloud cover increasing through the day. Light temperature inversion in place, cool air in the valley, warmer above freezing air between 1500 m and 2500 m, light to moderate south/southwest wind, no precipitation expected.FRIDAY: Overcast, light temperature inversion in place, cool air in the valley, warmer above freezing air between 1500 m and 2500 m, light to moderate southerly wind, 1 to 2 mm of precipitation expected.SATURDAY: Overcast, freezing level around 900 m, moderate to strong southwest wind, 1 to 3 mm of precipitation expected.

Avalanche Summary

On Tuesday reported avalanche activity was limited to snow balling and pin wheels on north aspects.

Snowpack Summary

On Sunday a slight crust began to form on south and southwest facing aspects as warm temperatures and sun combined to moisten the snow surface. By Tuesday the upper 5 cm of the snowpack had started to become moist, even on upper elevation northeast facing features. On December 28th and 29th two successive storms produced 50 to 80 cm of snow. On December 29th and 30th strong to extreme winds out of the southwest, south and southeast created widespread wind effect. Time and warm temperatures have allowed this snow to settle and bond well with the underlying surface. The exception may be with wind slabs in more extreme terrain and isolated pockets of buried surface hoar below treeline. A widespread melt-freeze crust may still be an issue in the northern portion of the region where it's down 50 to 70 cm below the surface, but is likely trending towards dormancy. Around the Coquihalla this interface is now thought to be part of a well bonded mid-pack. The lower snowpack is generally strong and well settled.

Régions couvertes