Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Thick slab avalanches that could bury or injure you could be triggered by a human on Thursday. We've seen unusual avalanche activity in the last couple days, and identifying which slope will slide has been tricky, so consider steering around steep terrain, especially in high-consequence areas. Wet loose avalanche activity on steep slopes on the southern half of the compass is expected to occur as the sun intensifies during the day. 

Avalanche problems

  • Wind Slabs

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

    Thick natural and human-triggered slab avalanches occurred both to the north and south of the West Central zone on Wednesday. Check out the Forecast Discussion for an involvement in the Baker backcountry on Wednesday which resulted in injuries. We can expect similar conditions in the West Central zone. Failures occurred 2 to approximately 5 feet deep, and they have some unusual characteristics. We aren't certain where all the avalanches have been failing, but many failed on the new snow/old snow interface, as storm slabs would. Some slopes slid while similar neighboring ones do not. We believe these avalanches are occurring in areas where wind may have deposited slightly thicker layers, but differentiating between the slopes that may slide and the neighboring ones that may not is borderline impossible. Surfaces in most areas look similarly wind-affected so you can't identify them that way. 

    This isn't a day to try and outsmart the problem, as resulting avalanches could be large and unsurvivable. Slopes are expected to become less reactive as each day passes, but it will remain possible for a human to trigger an avalanche on this layer on Thursday. Depending on where you are in the zone, you could see more or less activity on this layer. The problem we've got right now still fits into the Moderate danger level, but it's a bit like gambling with whether you'll trigger an avalanche or not if you get out on steep slopes. Higher-consequence terrain, such as large slopes over 35° or ones that contain terrain traps are locations it would be wise to avoid on Thursday. If you see any obvious red flags such as long shooting cracks from your feet or sled, or recent nearby avalanches, avoid nearby steep slopes also. When in doubt, steer around slopes greater than 35°. 

     

     

     

     

    (3/14/2023) A D1.5 human triggered avalanche which likely occurred sometime early afternoon. Suspected failure on new/old interface. Suspected crown height of ~45cm. W, 5800' Photo: Irene Henninger

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    This is the first day we're expecting full sun and higher temperatures. As the day progresses, pay attention to snow surface conditions, and start noticing when surfaces transition to wet sticky snow under your feet. Even if you don't have wet snow underfoot, nearby steep slopes could be getting intense sun and moistening. Areas that were previously light, low density, dry snow are where wet loose avalanches will be most active. Steep slopes are expected to moisten, and rollerballs will start rolling down.  They may be followed by wet loose avalanches. Avoid steep slopes where you see rollerballs or small wet loose avalanches, and steer around the underlying lower-angle slopes as well. You can expect activity to start on steep, east-facing slopes in the morning before the sun shines directly on south, and then westerly slopes in the afternoon. There is a small chance that one of these wet loose avalanches could also step down and trigger a larger slab avalanche. 

    Rollerballs like this are good indicators that wet loose avalanches could follow. 

    Photo: Matt Primomo

Avalanche Discussion

We received reports of an avalanche accident in the Mt Baker backcountry of the West North zone on Wednesday, March 15th. Preliminary information indicates 2 backcountry tourers were ascending the SE side of Slate Mt when the avalanche occurred. (SE, approx. 6100ft) One member was caught and carried by the slab. They sustained significant injuries and were evacuated from the scene by helicopter. NWAC is working with Bellingham Mountain Rescue to gather more information. Check out the media gallery for other recent avalanches in neighboring zones. 

Around 2-3ft of snow fell in the zone Sunday to Monday, and a few more inches fell Tuesday night into Wednesday. Numerous avalanche were reported in neighboring zones during the larger storm, and some small wet loose and additional slab avalanches have been reported since. Cornices have grown very large and are at high risk of falling, so stay far away from their edges and away from slopes underneath them on Thursday. 

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