Avalanche forecast

Seward and Lost Lake

Chugach National Forest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
Out of date — this forecast expired last year. You’re viewing past conditions, not the current bulletin.

Highlights

The avalanche danger will start out MODERATE and rise to CONSIDERABLE as the air temperature and sun melt the snow surface. Many large wet loose avalanches occurred in the last 2 days, which makes this the most concerning problem today. These avalanches are difficult to escape and have the potential to trigger a larger and more dangerous slab avalanche. Glide cracks are less common in Seward as they are in the northern zones, but the ones on Mt. Marathon could release at anytime and it's best to avoid being underneath them. As surface crusts break down, or where they don't exist, a person could also trigger a large avalanche on a layer of buried surface hoar that is 2 to 3' deep in Seward. There is a lot of uncertainty with the timing of dangerous conditions and these problems can be avoided by choosing low angle slopes. 

Avalanche problems

  • Loose Wet

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

    Recent avalanches: In the Seward area, recent avalanches, as far as we know, have been wet loose, some of which have been very large in the last 2 days with warm temperatures and sunshine.

    All the activity in the afternoon the last few days, and another warm day forecast today, means avalanche conditions will be dangerous this afternoon, or even this morning, if there are places that didn't freeze hard last night. High clouds are forecast to come in this afternoon, which could cool things off and make these problems less likely, but that depends on many factors like air temperature, timing of clouds, and potential greenhousing.

    Wet loose avalanches will be more likely for a person to trigger as the snowpack warms through the day. These avalanches could be bigger today than they have been and they have the potential to trigger a larger slab avalanche. A scary sign of a wet slab collapse was observed just below 2.000' on a southwest aspect of Center Ridge yesterday. This occurred in Turnagain Pass, but weather conditions have been similar in Seward. Even relatively small wet loose avalanches can be difficult to escape and the consequences of being caught in a wet slab are severe. If your boot is sinking to your mid-calf it's time to look for colder snow. Although this could lead you to problem 2 described below.

    There is a new glide crack on the south side of Mt. Marathon pictured here. This could release into a destructive glide avalanche at anytime and has the potential to cross the valley of Lowell Canyon where people hike and walk their dogs. 

    Cornices are also failing in the heat of the day. Some cornice fall has triggered large avalanches below, so this is another reason to avoid being underneath steep slopes in the afternoon. 

    (4/1/2025)

    A new glide crack opened on the south side of Mt. Marathon. This one could run across the flat terrain in Lowell Canyon.

    Photo: Mik Dalpes

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Although this has moved to problem 2 with all the wet snow problems that are occurring, we still think a person could trigger a large avalanche on the layer of buried surface hoar that is 2 to 3' deep in Seward. We have some uncertainty as to how likely it is for a person to trigger an avalanche on this layer, but the history of this layer's behavior has made it difficult to trust. It has failed after there are many tracks on a slope, and it has been triggered remotely and from low angle terrain in Turnagain Pass. Lack of recent avalanches on this layer in Seward and snowpit information suggests this problem may be more difficult to trigger in Seward than it is in the northern zones. 

    On mornings when a stout crust has formed (maybe not this morning as it is especially warm in Seward), conditions are generally safer as this crust can protect us from impacting the buried surface hoar and causing it's collapse. However, the timing of crust break down is tricky. If you are choosing to ride steep slopes look for small terrain features rather than large open bowls. Also ensure there are no terrain traps below like gullies or depressions where the snow could pile up and make a rescue difficult. 

    (3/27/2025)

    That thin gray line is the layer of surface hoar that we've been concerned with since the middle of February.

    Photo: Andrew Schauer

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