Boletín de aludes

Olympics

Northwest Avalanche Center
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Peligro de aludes

Mon
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
3 · Notable
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Desactualizado: este boletín caducó 5 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Multiple nights without a solid refreeze enable meltwater to rapidly unglue the fabric of the snowpack. Resulting avalanche activity may be large and difficult to manage. Plan to travel and return early, choosing routes that limit the amount of time you spend underneath large and complex slopes.

Problemas de aludes

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2

    ONP Rangers reported wet and gloppy snow 4-8" deep on most aspects by noon on Saturday. With sustained warm temperatures, larger avalanches could result from thickening wet, saturated surface snow. Avalanches could originate from steep and rocky terrain above you and travel far downslope. Plan your day to avoid traveling below large avalanche paths particularly as temperatures rise. Natural or human-triggered wet slides may occur on slopes steeper than 35 degrees once the sun rapidly breaks down a shallow crust. Once you sink past your ankle, seek out lower angled or more frozen snow.

    (4/16/2021) Example: A large natural wet loose avalanche which occurred in the last 24 hours on Cathedral Crag on a southeast aspect at 5000ft.

  • Glide Cracks

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–3

    Over in the Cascades, several large (D2) and very large (D3) avalanches occurred on Friday and Saturday. We know the terrain in the Olympics has the same potential. Frequent fliers have yet to produce glide avalanches and that has us concerned after so many hot days. Water is moving in the snowpack and in many cases reaching the ground. Glide slabs can fail without warning at any time of the night or day. Avoid traveling on or underneath any slope where you see crevasse-like glide cracks.

    (4/16/2021) A glide avalanche which occurred Thursday (4/15) night on Goat Mountain's West Peak. The crown is well over 10 feet deep. Photo: Andi Nelson

Avalanche Discussion

The temperature has been above freezing at Hurricane Ridge since August 13th at 8 AM making 5 straight nights of above-freezing temperatures going into Sunday. The temperatures have also been on an upward trend with Saturday hitting 62F! Considerable danger with loose wet avalanches seems very normal at first glance. However, this stretch of hot and sunny weather will likely lead us into the first widespread spring shed cycle of the year. Simple red flags like widespread avalanche activity, recent large avalanches, 5 nights above freezing, and temperatures increasing into Sunday all have us concerned about the potential development of dangerous conditions Sunday. Through Saturday, the Hurricane Ridge area produced surprisingly limited avalanche activity, but we think that may not last. 

During spring snowpack shedding cycles, many types of avalanches can come into play. Cornices grew large all winter and now sag along many ridgelines. They may collapse, entrain snow, and/or trigger other avalanches. Below the surface, many layers still exist within the snowpack where water could pool and cause a wet slab. Predicting when, where, and what type of wet spring avalanche you may encounter is incredibly challenging. Fortunately, the travel advice during these shedding events is the same. Travel and return early before the danger increases dramatically. Choose routes with plenty of options to adjust to the rapidly changing spring conditions. This includes making sure you have a safe route back to your car. Pay attention to the terrain above you. It may warm quicker than where you travel. Use routes that help limit your exposure to large and complex avalanche terrain, especially during the heat of the day. 

This is the final full avalanche forecast product of the 2020-21 season. As our capacity thins during the warmer months, please continue to share your observations and make use of our mountain weather forecasts (daily through the end of April). From all the forecasters at NWAC, thank you for all your support that makes this product possible and we look forward to resuming full operations in late 2021.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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