Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

MODERATE hazard remains near and above treeline today while LOW danger exists at lower elevations. Low likelihood but high consequence persistent slab avalanches remain our main concern today. Fresh wind slab development may also be possible near and above treeline on northerly and easterly aspects. Evaluate snow and terrain carefully and use terrain choice to increase your safety margin and limit your exposure.

We have received several reports from users that public observations were not being submitted over the past couple of days.  This issue appears to have been fixed.  Thank you for sharing your field observations and please continue to do so, your observations are invaluable to the forecast!

Avalanche problems

  • Persistent Slabs

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

    Persistent slab avalanches are becoming harder to trigger, this does not however mean it will be impossible. Recent field observations continue to show signs of unstable snow including collapsing, shooting cracks, and propagating test results. Large triggers such as a small wind slab avalanche or a cornice fall may be required to initiate a persistent slab avalanche today however, shallow trigger points such as buried rocks or small trees are areas of concern for the backcountry traveler. These are areas where the weight of a skier/snowboarder may be enough to initiate slab failure. While the likelihood of triggering a persistent slab avalanche is very low, the consequence of doing so is high. Avalanches breaking on these lower week layers have the potential to be quite large and destructive.

    Persistent Slab problems challenge our patience, and managing this problem requires extensive evaluation and deliberate terrain choice.  Don’t be afraid to investigate the lower reaches of the snowpack to see if old snow is present in the areas you wish to travel. This may mean digging all the way to the ground if you suspect old snow is present. Remember that persistent slab avalanches often propagate across and beyond terrain features that would otherwise confine surface instabilities such as wind or storm slab. Persistent slab avalanches can be triggered from lower angle terrain, the bottom of a slope, and in some cases, remotely triggered from adjacent terrain. Give yourself a wide safety margin, be wary of hazards that may reside above you, and use terrain choice to limit your exposure.

     

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Generally speaking, windward slopes in the alpine are pretty well stripped and limited amounts of loose surface snow remain available for transport.  However, with continued strong winds out of the southwest today it will be wise to be on the lookout for fresh wind deposits on northerly and easterly terrain near and above treeline. Blowing snow, large drifts, recent cornice growth, uneven snow surfaces, and stiff hollow feeling surface snow are all clues that indicate nearby wind deposits. Do your own localized assessments and be suspect of terrain features that encourage drifting such as the leeward sides of ridgelines, gully features, and cross-loaded depressions. Keep in mind that even a relatively small wind slab avalanche may be enough to trigger a much larger persistent slab avalanche in the right location.

Avalanche Discussion

While triggering a large and destructive persistent slab avalanche has become unlikely the potential size of such an avalanche breaking on these weak layers deserves extra consideration. This type of situation is particularly hard to manage. Keep in mind that the weak layer of concern is much more contiguous on northerly and easterly aspects particularly near and above treeline. At lower elevations or on more southerly aspects with full sun you are much less likely to find a snowpack with poor structure.   Be safe out there and enjoy the sun today, It may be our last dry day for a while!

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