Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

On a regional scale, natural activity has become less likely however, it may still be possible to trigger a large avalanche. Wind slabs ranging in size and sensitivity remain our greatest concern but lingering storm instabilities and the potential for warming snow are worth keeping in mind.  Be on the lookout for signs of instability today. Evaluate conditions carefully and build in terrain margins to account for changing conditions.

Avalanche problems

  • Wind Slabs

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

    Expect the size and sensitivity of reactive wind slabs to increase as you travel higher in elevation today. Burried near-surface facets may add sensitivity to this problem and increase the potential for wide propagation. It will be important to monitor for continued wind transport as wind speeds increase this afternoon and be prepared for deteriorating conditions during periods of continued snowfall. Recent avalanche activity, cracking within the surface snow, recent cornice growth, and hollow upside-down feeling snow, are all clues that indicate nearby wind deposits. Be suspect of terrain features that encourage drifting, such as the leeward sides of ridgelines, mid-slope rollovers, gully features, and cross-loaded depressions.

  • Storm Slabs

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

    Storm instabilities, both slabs and sluffs are expected to stabilize relatively quickly today but at least 4 small storm slabs were triggered in steep north-facing terrain yesterday. While natural activity will become unlikely, human-triggered avalanches could be possible in specific areas. Adding complexity to this problem is the potential for buried near-surface facets at the interface. Steep unsupported terrain over 35° in shaded areas sheltered from the wind will be areas of concern for storm instabilities today.  Be cognizant of your exposure to terrain features that increase the consequences of avalanches. This includes road cuts, gully features, cliff bands, and mid-slope depressions.

    Remote triggered D-1.5 storm slab avalanche (SS-ASr) on top of the last formed crust interface on a NE aspect at treeline.

Avalanche Discussion

As we enter a period of more quiet weather and a generally stabilizing trend there are still several areas of uncertainty to consider.  Our winter season continues to be unseasonably cold which has led to atypical Sierra conditions for late March. Top of mind for the forecast team is the potential for near-surface facets buried under our recent storm loads. Observers reported shooting cracks, collapsing in the upper snowpack, and several human-triggered avalanches yesterday including one avalanche that was triggered remotely by a snowmobiler.  In times of high uncertainty, it is important to dial back and build wide terrain margins into your field plan to account for the unknown. As the sun rises higher in the sky we also have the potential for warming snow today. Don’t be surprised to see roller balls and even small surface sluffs develop on solar aspects today particularly if the skies clear and the winds underperform the forecast.

Our winter full of high-intensity storms continues to have major impacts on communities, infrastructure, and road crews. Considerate travel choices and strategic parking will be appreciated if you decide to venture out today. With good coverage at lower elevations this winter, recent avalanches have been running further, impacting roadways and buildings in the communities of Virginia lakes, Mono City, June Lake, and Aspendell. It is important to practice good run-out awareness. Triggering an avalanche above infrastructure could have devastating consequences.  Remember that it often takes multiple passes to clear roadways and trailhead parking. Road crews are working overtime to allow access to communities that have been stranded by heavy snow, avalanche activity, and flood damage. Blocking snow drifts, travel routes, and snow piles makes it impossible for road crews to continue their work.

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