Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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

LOW avalanche danger this morning will rise to MODERATE avalanche danger as the day warms up. Loose wet avalanches will become possible again today on slopes where wet snow forms. While triggering a wind slab has become unlikely except in a few isolated places, cornice failures remain possible today especially as warming weakens the cornices. Avoid slopes where wet, unsupportable snow exists and complex or extreme terrain where isolated wind slabs may exist. Give all cornices a wide berth.  

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    Triggering a lingering wind-slab avalanche should be unlikely in most places today, and the light easterly winds combined with a lack of available snow means that new winds slabs are also unlikely today. However, unlikely does not mean impossible and some isolated wind slab instabilities may exist in some places. High elevation wind-loaded slopes, couloirs, gullies, unsupported slopes, and other complex or extreme terrain represent the best places to find one of these isolated wind slabs.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Sunny skies and warm daytime temperatures should provide sufficient warming to melt through last night's refreeze. Once this refreeze melts, loose wet avalanches will become possible on steep slopes. Some of these loose wet avalanches could still entrain enough snow to cause problems for backcountry travelers especially if they occur in an area where terrain traps like gullies, creeks, or cliffs could magnify the consequences of an avalanche. The sun-exposed E-SE-S-SW-W aspects hold the best potential for loose wet avalanches today, but enough warming could occur for some loose wet problems to also exist on some northerly aspects. Loose wet avalanches should comprise the majority of the wet snow issues today, but some isolated wet slab avalanches are not impossible in sun-exposed areas on any aspects/slopes where the recent snow has not been through a significant melt-freeze cycle.

    Sinking into boot-top deep wet snow, roller balls, pinwheels, or other signs unsupportable wet snow can represent clues that loose wet avalanches have become possible and that the snow has likely become less fun to recreate on. Get out early and find slopes with only a couple inches of wet surface snow and a supportable refrozen crust below for better and safer recreation. Once the snow starts to become wet and unsupportable, move to a colder aspect or head down and enjoy the spring afternoon in other ways. 

  • Glide Cracks

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    The large cornices above many wind-loaded slopes will remain fragile today and cornice failures are possible. The sun and warm temperatures will make these cornices even weaker as the day warms up. Give these cornices a wide berth and stay well back from their edges. 

Avalanche Discussion

Yesterday we received a report of a human-triggered cornice failure on the north side of Castle Peak. No other observations or data came in from yesterday. Recent observations from Tues. and Wed. showed the storm snow starting to transition towards corn snow, but it had not been through enough melt-freeze cycles to fully transition as of Wed. afternoon. Observations from Wed. also revealed that the sun and warmth can quickly melt through the overnight refreezes with the snow becoming wet and unsupportable in places by mid-day.

The last advisory of the season will occur April 23rd. Thanks to all who have supported the avalanche center. Click here for more information regarding the scheduled end date.

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