Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

A little bit of  snow could build new avalanche issues in wind-loaded areas and on steep sunny slopes. While these hazards will be the most in your face, they should also be easy to spot and avoid.

Avalanche problems

  • Wind Slabs

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

    Windy conditions early Wednesday morning could build a fresh batch of shallow slabs near exposed features. Fortunately, these wind slab pockets should be easy to spot and avoid. Look for blowing snow and textured surfaces to figure out which features could hold one of these small new avalanches. 

    A less likely, but bigger concern could be running into an older hard wind slab form Monday night. These deep avalanches could linger in rocky alpine terrain. While they may be tough to trigger, the could release above you with little or no warning. The best way to deal with this tricky problem is to simply stay out of complex rocky areas, especially when you see near by cornices.

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Minimal new snow should help limit the size and scale of this problem Wednesday. However, with new snow and sunshine it's on our minds. Many rollerballs and loose wet slides occurred on Tuesday around the zone. So, you’re primary concern will be small slides involving the new snow. If the sun comes out in the afternoon, you will see snow shed from trees and rocks. This will trigger piles of rollerballs or small loose wet slides on the slopes below. Some of these avalanches could run quickly on a new crust. So, pay attention to the terrain above you. Don’t let one of these small slides push you into a creek or over a cliff.

    (3/14/2023)

    Natural loose wet avalanche near Crystal Mt on the first sunny day following a storm. 

    Photo: Andy Harrington

Avalanche Discussion

This storm looks pretty minimal for the West South zone. Instead, the winds could be the more impressive factor. Even still it should be enough new snow to keep conditions from becoming “generally safe.”

At this time of year the snowpack quickly becomes aspect dependent. Sunshine on Tuesday caused plenty of rollerballs and small loose wet slides. It also formed a new crust on the surface. 

In more shaded terrain, cold snow lingered despite the sunshine and mild temperatures. The recent storm (Mon-Tues) brought 10-15 in to most of the zone (with more at Mt St Helens). This snow seems to be bonding well with the old (3/12) interface. 

We have had a few notable avalanche observations this week. On Tuesday, we had two reports of the same avalanche in the Cowlitz Chimney’s area of Mt Rainier NP (NE, 6300ft). This very large slide likely failed during the recent warm storm. Two other very large avalanches occur on Mt St Helens early on Monday during the peak of the storm. The larger (D4) ran from near the crater rim to very low in the terrain (E, ~8000ft). We don’t know if these slides failed on older deep crusts or in just extremely wind-loaded locations. Either way, take note if you’re heading into remote alpine areas.

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