Bollettino valanghe

Cariboos

Jan 6 – 7, 2012Avalanche Canada
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Archiviato · scaduto 15 years ago

Pericolo valanghe

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

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–5
    Previous windslabs should be getting less reactive on Saturday. Expect new windslabs to develop Saturday night that may become very touchy by Sunday as the temperatures rise and the winds increase.

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    3–5
    Warm temperatures and strong winds have caused rapid cornice growth which may not be well supported. Try to reduce your exposure beneath these large unstable masses of heavy snow.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    3–7
    Reports of activity on this layer have decreased. Large triggers like explosives and cornice fall have continued to release avalanches that fail down to this weakness. Steep open slopes near treeline may be the most suspect for human triggering.

Confidence

Fair - Freezing levels are uncertain on Sunday

Weather Forecast

Flurries during the day on Friday should accumulate a couple of new cm by Saturday morning. A weak ridge of high pressure building over the coast is forecast to develop strong winds from the west or northwest and warm temperatures in the Cariboo. Moderate precipitation is expected to begin by midnight and continue during the day on Sunday. The freezing level is expected to rise to about 1800 metres in the Cariboo and West Monashee by Sunday morning. It looks like most of the snow will fall in the North and West of the Interior ranges. Expect moderate to strong northwest winds on Sunday becoming strong from the west in the South Columbia and Purcells. Cooler air is expected to move in to the region from the northwest on Monday. Precipitation amounts are un-certain at this time. Chinook conditions are expected for the Rockies.

Avalanche Summary

No new reports from this region. I suspect that the poor visibility and travel conditions have limited observers ability to report. Explosives testing to the south of this region has produced very large avalanches releasing in the mid-december surface hoar layer.

Snowpack Summary

Another 10-15 cm of new snow overnight arrived with cooler temperatures. The recent snowfalls add up to about 50-70 cm of "storm" snow that has been available for wind transport. The warm temperatures and high freezing levels caused the wind transported snow to become a well consolidated slab. The height of snow in the region is between 200 cm in the drier areas and close to 300 cm in the wetter areas. The storm has been very mild, with freezing levels near 1800 metres on Wednesday. The temperatures started to fall early Thursday morning when the rain and snow moved out of the region. The winds have been very strong from the south and southwest. Expect to find windslabs on north and northeast aspects in the alpine and at treeline. There may be a rain crust developing below 1600 metres as the freezing levels drop back to valley bottom. The previous storm snow is now fairly well consolidated and makes for a generally strong mid-pack. A surface hoar layer buried around Christmas is well preserved, now buried around 80 cm below the surface and is producing sudden "pop" results in stability tests. A surface hoar/facet/crust interface from mid-December is buried 100 to 150 cm deep and is still reactive to natural and human triggers.

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