Bollettino valanghe

South Rockies

Nov 24 – 25, 2017Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 9 years ago

Pericolo valanghe

Sun
Mon
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Apri la mappa completa

In sintesi

If the rain-soaked snow freezes as expected through the weekend, avalanche hazard will follow a decreasing trend until the next storm on Sunday. Please treat this forecast as an initial assessment, as we have little information at this time.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–2
    5-15cm of new snow fell at the tail end of the storm, as temperatures cooled and the rain turned to snow. Watch for wind slabs from redistributed snow on north easterly slopes at higher elevations.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–3
    We know there's a crust buried approx. 50cm below the surface, but don't know much about how likely avalanches are on it. Once there's a new thick crust on the surface, this lower layer may become less of a problem. Until then, assume it's a player.

Confidence

Low - Due to the number of field observations

Weather Forecast

We're looking at relatively benign weather until Sunday afternoon, when a brief but intense cold front will bring rain and then 10-15cm snow by Sunday night. Saturday: Dry. Freezing levels initially around 1500 m, but increasing later in the day. Light southwesterly winds, increasing in the afternoon.Sunday: Rain early afternoon changing to flurries (10-15 cm possible). Freezing levels 2200m decreasing to surface by the evening. Winds moderate southerly. Monday: Scattered flurries. Freezing level around 1200 m. Moderate westerly winds.

Avalanche Summary

There are few observers right now. Several loose wet avalanches to Size 1 were reported at the tail end of the rains (Thursday). Some persistent slab activity to Size 2.5 was reported to the north in Kananaskis country. Elevations ranged from 2400 to 2600m on Northeast through Northwest aspects. I suspect avalanche activity will taper off with cooling temperatures on the weekend.

Snowpack Summary

Rain and warm weather have resulted in a widespread wet upper snowpack. The freezing level rose to approximately 2700 m on Wednesday and Thursday meaning very few places, if any, will have escaped the melt. The last three days have seen the snowpack diminish by approximately 20-30 cm.Some areas saw 5-15 cm of snow at the tail end of the storm and the possibility of thin windslabs exists. Expect treeline snow depths of around 45 cm in the Elk Valley and more like 80 cm further south in the Flathead in sheltered areas. A crust that formed around Halloween has been reported within the snowpack that may lie around 40-50 cm below the surface.

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