Bollettino valanghe

Summit Lake

Chugach National Forest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

Strong winds will make human-triggered avalanches around a foot deep likely, with a smaller chance of some natural avalanches today. The new and windblown snow from the past two days is also adding stress to a weak layer of snow buried around 2' deep that may produce larger avalanches. You can avoid these problems by staying off steep, wind-loaded slopes.

FRIDAY'S AVALANCHE OUTLOOK:  We are expecting to see the weather quiet down tomorrow, which should improve avalanche conditions. The main concerns will be the same as today, with a slightly lower chance of triggering an avalanche. The most likely places to run into trouble will be in steep, wind-loaded terrain at upper elevations. We will publish our next avalanche forecast on Saturday.

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SPECIAL ANNOUNCEMENTS:

End of Season Operations: We have transitioned to our late season schedule. We will issue avalanche forecasts on Tuesday, Thursday, Saturday and Sunday for the second half of April. We will issue our final forecast of the season on Sunday, April 27.

Risk management research: If you have been traveling in avalanche terrain for at least one season and want to help avalanche researchers develop new tools to assist individuals with managing risk in avalanche terrain, check out this 1-2 minute survey. Participants will be entered to win prizes from Jones Snowboards, BCA, and more!

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    The mountains near Summit Lake received around 6 to 8" snow from the storm that started Tuesday night and is exiting this morning. This was accompanied by very strong southeasterly winds, which are expected to ease slightly today but will still be strong enough to continue blowing snow. As a result, it will be easy to trigger an avalanche in steep, wind-loaded terrain. 

    The most likely places to find unstable snow will be on steep slopes near ridgelines, convex rolls, and in loaded gullies. Watch out for clear signs of reactive snow like shooting cracks and collapsing, and be aware that you won't always get these warnings even when conditions are unstable. More subtle clues like stiff snow sitting on top of softer snow should also be cause for concern. Keep in mind, all of this new snow is sitting on top of a snowpack with a problematic buried weak layer which may produce a much bigger avalanche. More on this in Problem 2.

    Cornices have been growing and collapsing during the active weather over the past two weeks. We can expect this to continue as the wind keeps blowing today. Avoid lingering under large cornices, and give them plenty of space if you are traveling along ridgelines.

    Estimated storm totals from Tuesday at midnight through Thursday morning: 

    • Girdwood: 2.5" Snow Water Equivalent (SWE)/2' snow above 2000'
    • Turnagain Pass: 1.5" SWE/1-1.5' snow
    • Summit Lake:  0.7" SWE/6-8" snow
    • Lost Lake: 1.5-2" SWE/10-18" snow

    (4/17/2025)

    Snow totals from 4 am Thursday through 4 am Friday. Most of the snow in the northern zones will fall between 4 am and 6 am, but the storm is expected to linger in Seward through the day.

    Photo: NWS Anchorage

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2

    This most recent round of wind and snow has added extra weight to the layer of buried surface hoar that we have been tracking since mid February. We have yet to see an avalanche fail on this layer in the Summit Lake zone, but we saw widespread activity in other zones over the past two months. It is very hard to tell just how reactive this layer is, but this most recent event has increased the likelihood of triggering a large avalanche. 

    This layer has been tricky to assess, often giving misleading test results even when conditions are dangerous. Keep this in mind if you are moving into steep terrain today. The biggest issues will be on wind-loaded slopes, but you may also find this problem in sheltered terrain. With problems like this, the best option is to just avoid steep slopes.

  • Glide Cracks

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    Wet avalanches remain a concern in all areas today. We have limited info with the extent of natural avalanche activity during yesterday's storm, but with rain up to 1500 to 2000', it is likely there has been a variety of wet snow avalanches. Glide avalanches will remain a concern today. These are large and unpredictable, and the only way to manage the problem is to avoid traveling under open glide cracks.

    (4/15/2025)

    Fresh glide avalanche seen in PMS Bowl on Magnum Ridge. This overran the common skin track to gain the ridge.

    Photo: Ari Stiassny

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