Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

New snow layers up to 2 feet deep may avalanche with a human trigger. Additionally, you could trigger an avalanche on weak layers buried several feet deep. Conservative terrain selection remains critical, so stay off open slopes steeper than 35 degrees at this time.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    You could trigger avalanches in the new snow that fell over the weekend, which amounted to around 2 feet. Depths of avalanches may range from about 6 inches to 2 feet deep. These avalanches could bury, injure, or kill a person, or could even trigger deeper weak layers as they run downslope resulting in very large avalanches. 

    Wind may have affected the snow at higher elevations, developing into firmer slabs. Search for changes in the snow, noting when it becomes stiffer and more pillow-like in appearance to alert you to the presence of wind slabs. In areas where the wind hasn’t affected the snow surface, storm slabs or loose dry avalanches may release on slopes steeper than 35 degrees. Until more time has passed avoid slopes steeper than 35 degrees.

    (2/5/2021) Snowmobile triggered avalanche in the Mt. Baker NRA at the toe of the Easton Glacier on southerly aspect near 5000ft. The snowmobiler was caught by the avalanche and carried a short distance with their snowmobile partially burried. The avalanche looks to have failed 6-12in deep on the 2/4 interface with an impressive crown breaking several hundred feet wide.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    It is possible that you could trigger a deep persistent slab avalanche on steep slopes above 4500ft. There are many reports of avalanches failing on this layer in the last two weeks.  It is buried around 3 to 5+ feet deep at this time. The amount of snow on top of the weak layer is making it more difficult to trigger, however, if someone were to find a shallower spot and trigger an avalanche, results would be catastrophic and probably unsurvivable. A snowshoer might get away without triggering an avalanche on this layer, but there is no doubt that a snowmobile could trigger one.  It is unknown how widespread this persistent weak layer is, as it has been found on some slopes and not others. 

    You will not find obvious signs of instability like you might with other problems like wind slab avalanches. You need to dig down to the Jan 13 crust and make note of the layer above it, observing the state of any persistent grains and how readily those layers just above the crust fail. I wouldn’t place all my bets on one pit for this sort of problem, either. The game is too dangerous to play the odds on. Broad open slopes and large features in areas steeper than 35 degrees is where the highest likelihood of finding this problem is, so avoid those slopes at this time.

    (2/3/2021) A person touring along the ridgeline from Artist Point to Huntoon Point remotely triggered a cornice that fell onto the slope below triggering this large avalanche. The avalanche occurred on a NE aspect at 5000ft and failed about 1 meter deep on the 1/24 interface.

Avalanche Discussion

Preliminary avalanche incident information Monday February 8th, 2021: Two snow bike riders were caught and buried by a very large avalanche in the mountains west of Salmon la Sac Sno-Park along Cle Elum Lake. One snow biker was partially buried and was able to dig himself out. The other rider was fully buried and killed by the avalanche. The avalanche occurred on a north aspect at 4400 ft in the Knox Creek drainage. This terrain lies in NWAC’s East Central forecast zone. Avalanche classification: HS-AV-R3-D3-O. 

All of us at NWAC want to extend our condolences to family, friends and the local community following this tragic event.  

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Many natural and human triggered avalanches occurred over the last two weeks, including involvements with both skiers and snowmobilers.  Check out one of the reports of a snowmobile involvement here.  A skier triggered avalanche in the Steven's Pass area on Sunday tells quite a story. Have a read here.  Avalanche problems related to new snow and wind are concerning enough, but the lingering deep slab instability poses a risk with even more uncertainty and higher consequences. A conservative mindset is crucial to getting through this period unscathed. Right now finding those lower angle areas or traveling through tighter trees are your ticket to surviving this rough period with the snowpack.  

The instabilities began after the atmospheric river event which ended with a stout 1/13 crust. Only a few inches of snow followed over the next 11 days, which weakened as it sat exposed to the sky. Snow began to fall Jan 24, and since then we have continued to see avalanches occurring on that Jan 24 interface, failing deeper as snow continued to accumulate on top. An extensive avalanche cycle occurred Jan 30- Feb 2 after a more intense period of snowfall (8.5in of water/4ft of snow at Heather Meadows), and several close calls occurred in the following days as backcountry users got out again. 

These conditions are not identical, but have similarities with other snowpacks nationwide, where avalanche fatalities have sadly trickled in over the last week (15 in total). Heading out onto a steep slope for any reason is not worth the consequence of not making it home that night. Have this in mind while you travel in the backcountry during this period of unstable snowpack conditions.

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