Avalanche forecast

Summit Lake

Chugach National Forest Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

The snowpack is complex right now due to a combination of dry snow problems on the surface, buried weak layers, and wet snow problems deeper in the snowpack. About 1' of new snow this week could cause human-triggered avalanches in steep terrain. If the sun comes out today the new snow could heat up quickly and cause natural avalanches on steep solar aspects. A buried weak layer about 1 to 2' deep could cause larger avalanches, although the distribution of this weak layer is isolated to sheltered terrain above 2000'. Finally, large wet avalanches and glide avalanches are possible. We recommend a conservative mindset to help manage this complex setup. 

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SPECIAL ANNOUNCEMENTS:

End of Season Operations: Starting next week we will transition 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.

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!

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Continued snowfall this week has slowly added stress to the buried weak layer of surface hoar, which is roughly 1 to 2' deep in the Summit Lake area. While we haven't seen any recent avalanches on this layer, we have seen concerning snowpit results in some locations. The most likely place to find this layer is between 2000 to 3000' in sheltered terrain. Sometimes buried surface hoar provides red flags like collapsing or shooting cracks as signs it is unstable. However, it is also possible to trigger an avalanche on this layer without any obvious signs of unstable snow. 

    To avoid this problem you can always stick to low angle terrain and avoid steep slopes overhead. If you choose to enter steeper terrain you can improve your safety margin by avoiding large start zones and terrain traps like gullies or cliffs in the runout zone. There is a lot of uncertainty about how widespread and how sensitive this weak layer is in Summit Lake, which makes for a challenging decision-making setup. We recommend a conservative mindset to manage the uncertainty with this weak layer.

    Wind Slab Avalanches will become likely if winds pick up this afternoon. With plenty of soft snow on the surface from the past few days of snowfall wind slabs can form rapidly at upper elevations. 

    Loose Snow Avalanches will become more likely if the sun pokes through the clouds today. Be on the lookout for steep solar aspects if the clouds break up during the day, especially on slopes with trees or rocks that will heat up quickly.

    Cornice Fall: Cornices have been growing during the active weather over the past week. These can release naturally and may trigger larger avalanches on slopes below. Limit spending time below cornices, and give them plenty of space if you are traveling along ridgelines.

    Overnight snowfall in Summit Lake as stormy and unsettled weather continues throughout the area.

    Photo: John Sykes

  • Glide Cracks

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

    During the brief breaks in cloud cover this week we have observed continued glide avalanches releasing across the forecast zones. This is part of the normal spring shed cycle, but these avalanches are unpredictable and very difficult to manage with limited visibility. The best way to avoid them is to steer clear of steep terrain overhead. If visibility allows, try to keep an eye out for glide cracks opening up that are often a precursor to avalanches releasing. 

    Wet Slab Avalanches: Underneath the new snow from this week the snowpack has largely transitioned to spring wet snow at low and mid elevations on solar aspects (east, south, west). On Fresno this week we found concerning structure in the wet snow layers, with multiple tests failing in a layer of wet faceted snow about 2' deep in the snowpack. If the sun comes out today we could see a rapid transition back to wet slab avalanche problems. Especially on steep south-facing terrain with trees or rocks poking through where the heat from the sun can quickly melt the snowpack. If the crust on top of the wet snow melts and you are sinking in deeply to wet snow while traveling this is a clear sign to avoid avalanche terrain. 

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