Bollettino valanghe

South Columbia

Jan 22 – 23, 2013Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 14 years ago

Pericolo valanghe

Thu
Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Danger ratings are based on snowfall starting early Wednesday. If it starts later, they would be one step too high for Wednesday.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–5
    The load from the storm snow could awaken the early January surface hoar layer. Distribution is patchy in sheltered areas and has been more reactive on S and SW aspects.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–5
    Storm snow might not bond to a variety of surfaces. New windslabs will form as the day goes on lee side of the forecasted strong SW-W winds in alpine and at treeline.

Confidence

Fair - Timing of incoming weather is uncertain on Wednesday

Weather Forecast

Tuesday night and Wednesday: The frontal system is pushing its way into the interior and precipitation should start around Wednesday morning. 10 to 15 mm (possibly more in W and S of region) is expected to fall during the day with moderate to strong winds from the SW in the alpine. Freezing levels will lower to valley bottom and the inversion will disappear. Thursday: A break before the next system. Expecting some clearing, winds tapering off staying from the same direction, temperatures also staying cool and freezing level to valley bottom.Friday: Expecting light precipitation and moderate SW winds.

Avalanche Summary

Numerous moist loose avalanches up to size 1.5 and snowballing on S facing slopes was reported.

Snowpack Summary

Storm snow accompanied by strong SW-W winds will create loose snow concern in sheltered areas and new wind slabs in the alpine and at treeline on lee slopes. These new layers will most likely be touchy for a certain time and could also put on the needed load to awake the deeper instabilities that have been unreactive to skier traffic lately. The new snow will be sitting on a variety of surfaces; sun crust on S facing slopes, surface hoar layer mostly found in shaded-sheltered areas below treeline, facets and old windslabs that were breaking down. The early January surface hoar layer found under the top 50-70 cm, which has been unreactive to skier traffic but still producing the odd sudden planar shears especially under the elevation of 1500 m. in sheltered areas, could become more reactive with this added load. Under these concerning layers, a strong mid-pack overlies a weak facet/crust layer near the base of the snowpack, which is now considered inactive. 

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