Bollettino valanghe

Bridgeport Avalanche Center

Bridgeport Avalanche Center
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Alta quota
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Sotto il limite
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Gusty winds, warm temperatures and fluctuating snow/ rain elevations, yesterday and overnight have spackled our snowpack.  Leeward ridgelines, catchment zones and north facing, above treeline are areas of greatest concern for slab avalanching.  Practice safe travel techniques, especially if entering this particular type of avalanche terrain.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    Above tree line, North aspects could still be harboring multiple layers of faceted snow from earlier in the season.  Depth hoar/basal facets at the base of the snow pack and near surface facets that were buried on this last storm cycle, about 18" from the ground.  With total depth of snow ranging from 60cm to 200cm in these shaded N aspects.  These isolated-stubborn areas that look to be gaining strength with the past week of warm weather are still a concern and can be triggered in the perfect spot.

    Chances of triggering an avalanche remain low, but with high consequence.  Varying snow depths in isolated terrain, and most likely rocky terrain in NE-N-NW aspects.  This Persistent Slab is becoming less likely with the warming temperatures we've been experiencing over the past week. But high elevation, north shaded aspects are still a concern. And with new warmer-wind loaded snow on top, it may activate the slab with the increased weight.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    The possibility of Loose Wet avalanches increased overnight with high rain/snow line to around 9500'-10,000'.   Snow water equivalent amounts over the past 12 hours at 9600' were .6" and 24 SWE was .9" with only 3 inches of new snow.  Where it should be closer to a 1:1 ratio.  .1" of SWE = 1" of snow.

    So with that being said, our already high snow line, just got higher and with rain on top of snow, the snow we did have will be saturated.  Wet Loose instabilities develop as sunshine, warming temperatures, and/or rain-on-snow wet and weaken the snow surface, causing it to lose cohesion.

    Temperatures have been above freezing for a majority of the past 4+ days with poor night time freezing recoveries.  Look for Wet snow instabilities like roller balls and unconsolidated granular snow. Wet Loose avalanches can also trigger larger slab avalanches that break into deeper snow layers.

    Solar/south facing aspects Below Tree Line, most likely is without snow.  

Avalanche Discussion

Yesterday was a full mixed bag of condtions.  At gate 1 or peoples gate on HWY 108, car temp read 54*F.  Lots of pavement intermixed with icy strips on the sled ride up the road to Leavitt Lake.  It was difficult keeping the sled from overheating as loose available snow to keep the sled tunnel radiator cool isn't available.  See pics of "Carbide Hill and Corner"

Last night brought windy and wet conditions with snow levels ranging from 9000-10,000'  with .6" of SWE  overnight.  This brings up concern for Loose Wet activity and Wind Slab possibility but in very specific areas.  Leeward facing (E-NE-N-NW) and NTL and ATL elevations that stayed cold enough to get snow and not rain, but in catchment zones and below ridges that the snow didn't get blown away. 

One of the bigger concerns is up high in the alpine, above tree line, where persistent weak layers are still isolated and unreactive. This heavier wet-wind loaded  snow on top of those layers may awaken a deeper slab problem. Until we get eyes on and hands in the snow, steering clear of steep, north facing slopes up high is the best call.

If going out today, be cautious, make a plan, have a solid partner, keep margins wide and step back until more information can be assessed.

Regioni coperte