Avalanche Forecast

Reports of natural and triggered avalanches continue in the Mt. Baker area. Periods of clear skies over the weekend allowed observers to view evidence of a unique and impressive avalanche cycle. Numerous avalanches were very large and destructive (some could destroy a house). Several ran full track to valley bottom. Many had very wide propagation (up to ¼ mile). The majority of avalanches failed on a weak layer (surface hoar and/or facets) buried 4-6ft deep.

Over the past week, Mt. Baker has received over 10” of water translating into several feet of new snow. Sunday brought an additional 2” of water with rain up to 5000ft and heavy snow above. More snow and wind over the next 24 hours will continue to overload our fragile and scary snowpack.

Dangerous and fickle avalanche conditions remain as active weather continues into the week. 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 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. You can find similar snowpack structure responsible for these avalanches in many other locations throughout the Cascades, including Stevens and Snoqualmie Passes.

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 - 12/16:  

• Mt. Baker: 75”

• Washington Pass: 35”

• Stevens Pass: 42”

• Snoqualmie Pass: 36”

• Paradise: 51”

• Crystal Mt Base: 29”

• Mt. Hood Meadows: 21”

• Olympics: mix of rain and snow, no net gain

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. Mt. Hood and Hurricane Ridge have low snow coverage below 5000’.

If you're out in the mountains, please let us know what you see.

Be cautious and get home safe.