Avalanche forecast

Banner Summit

Sawtooth Avalanche Center
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Avalanche danger

Wed
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

Very dangerous avalanche conditions exist. Nearly 3 feet of snow have fallen in the last 24 hours and another 8-12 inches will fall before the storm ends later today. Large natural and human-triggered avalanches are very likely today. Avoid avalanche terrain and terrain exposed to hazard from above.

The backcountry Avalanche Warning does not apply to the HWY 21 avalanche program.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Certain
    Size
    1.5–2.5

    As of 5 AM this morning we have added 3 feet of snow and 3.5 inches of snow water equivalent (SWE) to the snowpack in this zone. Another foot of snow is expected by the end of the day today. Temperatures will gradually climb through the day, reaching the warmest we've seen since Saturday. These conditions have created widespread slabs that are dangerous even in areas that did not hold snow before this storm and in areas that lack obvious weak layers. These slabs will be even larger and even more sensitive to your weight where the wind has been blowing. If you head into the backcountry you will be faced with hazardous conditions on steep slopes from the time you leave the car until you get back. Pay attention to what is above you in addition to the terrain you are traveling through—slopes will be avalanching naturally due to intense precipitation rates today.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    On shaded slopes at middle and upper elevations, the snowfall from this storm is overlying a very weak layer of faceted snow. This storm has pushed this weak snow up to and past its breaking point. Persistent slab avalanches tend to fail in ways that surprise even experienced backcountry travelers. They can break much wider than you might expect and wrap around major terrain features. They also may be triggered remotely—from a distance above, below, or to the sides of steeper slopes. 

    Yesterday, in the Baker Creek drainage, I remotely triggered an avalanche on this weak snow from a distance of 1/4 of a mile away. Yes, you read that correctly. Nearly every slope that I traveled over fractured like a pane of glass as the slab of new snow collapsed into the weak facets beneath. These slopes were not steep enough to slide, but had they been steeper these would have been avalanches. Watch the video at right to hear more about what I found.

Avalanche Discussion

It is on days like today when we realize how small and fragile we humans are. We live in a dangerous world, it will be hard to ignore the obvious signs of instability and avalanche activity today. This storm and its impacts will be something that the people who call this place home will talk about for a long time. I'm expecting to see avalanches of all stripes and sizes today, occurring throughout our region. This includes in urban settings on the valley floors.

  • Roof avalanches? Yep, there is plenty of snow for these. Warming temperatures will accelerate the creep rate of the snow. Be careful what is above you, wherever you find yourself.
  • Road-cut avalanches? Yep, steepened banks on the sides of roads and highways are prime candidates for avalanches. Snowplows often cause these as they throw snow off to the side of the highway.
  • Avalanches on small slopes above creek beds and in narrow draws? Yep. Be alert to terrain traps and the consequences of being buried by heavy snow in one.
  • Avalanches breaking hundreds to thousands of feet wide in alpine terrain? Yep, we have the weak layers and the storm snow for this too.

Today is no day to thread the needle. Mother Nature is practically yelling at us. Let's turn the dial way down, watch the fireworks, and thank our lucky stars that we have a snowpack all of the sudden. It has gone from zero to 100 in 4 days and it is going to take some time before we are sanely thinking about entering avalanche terrain. 

Regions covered