Avalanche forecast

Bridgeport Avalanche Center

Bridgeport Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 8 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Large consequential avalanches were human triggered yesterday just below leeward ridgelines, on northerly shaded facing slopes. Make your margins bigger, as these deep snow instabilities have very large and destructive potential.  Avoid terrain with high consequence and trapping runouts.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–3

    3 days of strong south/southwest winds and 12 iches of SWE has loaded slopes.  Multiple temperature fluctuations during the storm has created heavy wind slabbed snow over lighter less dense layers.   Look for these problematic wind loaded pockets below ridges, in start zones and above specific steeper consequential terrain.   Problem may also exist in isolated pockets (slabs) of steeper treed gullies and chutes.  This layer may also step down the weaker bed surface, talked about in problem 2.  Remember, wind can transport 3-5x the amount of snow fallen onto leeward slopes, creating huge dense and dangerous slabs. 

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3.5

    Multiple deep snow human triggered avalanches have been reported over the past 3 days since the this past Sierra storm dropped 12" of SWE in a 72 hour period.  This copious amount of snow was accompanied by gale force winds, creating recipe for ultra large leeward wind slabs just below ridgelines.  And these specific zones are/were still holding old rotten sugary snow from October and November storms.  In conclusion, high leeward ridgelines at the Sierra Crest and possibly sub crest ridgeline slopes are holding 15+ feet of dense wind packed wind slabs, sitting on a bed surface of old sugary faceted raincrust.  These are condsidered Deep Persistent Slabs and should be treated with the utmost respect and care.

Avalanche Discussion

  • 2 large avalanches were human caused just below the Sierra crest ridgeline on the North-Easterly facing slopes yesterday. Multiple snowmobilers were caught and carried. Atleast 1 sustained injuries and was airlifted to Reno.  One of the avalanches, had a steep runout and a terrain trap below of a semi frozen lake. The rider was swept across the lake in the avalanche debris and end up in the unfrozen slush on the far side of the lake, underneath his snowmobile. Members from his riding party and rescuers were able to pull him to shore and was transported via helicopter to the hospital.  

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