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RegisterDec 15th, 2018–Dec 16th, 2018
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You can trigger dangerous and surprising avalanches that could break widely across terrain features. Avalanche danger will rise with continued snow, wind, and a warming trend on Sunday. Careful route finding and cautious decision-making are essential.
A series of storms over the past week delivered over two feet of new snow to the Washington Pass area. This added load doubled the height of the snowpack and tested weak layers of buried surface hoar and facets. The result was a widespread natural avalanche cycle on December 11th. Recent observations confirm the potential for propagation on these weak layers buried 2-3ft below the snow surface.
Limited information exists for the East North Forecast Zone. If you head out in this area, please send us your observations.
We made it through our first strong winter storm and are headed into a weekend with dangerous and fickle avalanche conditions. Thick slabs of new snow (2-5 feet) are perched above a weak layer of faceted crystals. Avalanches triggered on this layer could be very large and life-threatening.
Reports continue to come in of very large natural and explosives triggered avalanches in the northern and eastern zones. For perspective, several of these slides have been classified as D3, or large enough to destroy a house.
Anyone accessing alpine areas should limit their exposure to areas where avalanches start, run and stop. In some places, the weak snow will talk to you by whumpfing and cracking. In other places, the heavy blanket of new snow is thick enough that it can give a false sense of stability while it masks the dangerous layering below.
Approximate snow totals from 12/10 - 12/14:
Mt. Baker: 55”
Washington Pass: 29”
Stevens Pass: 37”
Snoqualmie Pass: 28”
Paradise: 38”
Mt. Hood Meadows: 13”
Olympics: mostly rain
The change in the snowpack is pretty dramatic with elevation. The height of snow decreases rapidly below 4500’ at Baker and Washington Pass, 5500’ at Crystal/Rainier. The Passes have better low elevation coverage, but it's still pretty thin below 4000’. With additional warm storms in the forecast, this pattern is expected to continue for a while.
Be cautious and get home safe.