Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The upper snowpack remains wet and generally weak after multiple days of warm temperatures, periods of sunshine, and poor overnight freezes. This pattern continues to cause a rather prolonged spring-shed cycle and maintained wet avalanche concerns. Don’t linger underneath steep and rocky slopes, especially where you see cornices looming overhead.

Avalanche problems

  • Loose Wet

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

    Four days of above freezing temperatures created a generally wet and weak upper snowpack on all aspects and elevations around the Wet South zone. Yet another night without a solid freeze will only make this problem worse. While this isn’t the type of situation where you’re likely to trigger a loose wet slide on every slope, any steep terrain where you find wet snow deeper than your ankle should be suspect. Even if they are tough to trigger, at this point these slides could entrain older snow, grow bigger, and be difficult to escape. With some sunshine in the forecast for Tuesday, these avalanches might be most dangerous on sunny slopes. 

    Spring shed patterns like this bring a myriad of possible avalanches issues. Cornices may collapse, glides avalanches could release, wet slabs can fail, and blocks of snow might shed from rocks. These types of slides don’t always give warnings, and the prolonged warm weather is the best indicator. So, pay attention to the terrain above you and don’t linger underneath steep rocky terrain, especially where you see looming cornices.

    (3/25/2022)

    This natural wet avalanche occurred mid-day on 3/25 during a period of warm weather and filtered sunshine.  [E 6700']

    Photo: Dallas Glass

Avalanche Discussion

Monday will be the fourth or even fifth night without a solid freeze for locations around the West South zone. The longer we go into this period of above freezing temperatures, the greater our uncertainty grows regarding the possible size and likelihood of these spring avalanches. Tuesday has the potential to be the most active day of this shed-cycle with warm and sunny weather. Without a solid freeze, you may encounter wet and punchy snow right off the bat in the morning and starting early might not significantly reduce the hazard. While you may find a thin breakable crust in some open areas, expect this layer to quickly soften. 

The past week really pushed the mountains through a spring transition. On many slopes that means the upper snowpack changed to spring-like (melt form) snow. A more nuanced structure with lingering layers of dry snow could still exist in mid and upper elevations shaded terrain. These are the same areas where we recently dealt with a persistent slab issue across this zone. While it’s been 10 days since our last avalanche on the 3/8 facets over the Early March Crust, it’s hard to say how that layer may fair during this warm weather. It would likely take a cornice fall or other avalanche in just the right spot to get these grains to fail, but given the current hazard, that is not out of the question. 

At lower elevations, the snowpack is starting to melt and expse obstacles, creeks, and even bare ground. Fortunately, avalanches below treeline should stay relatively small and not pose too much of a risk.

Regions covered