Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
View on map

Avalanche danger

Sat
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
Open full map
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Though snowfall totals have not yet met expectations, the avalanche hazard is still expected to rise quickly throughout the day. New and drifting snow will become unstable at all elevations. Slab size will increase with elevation. Rapid loading could wake up weak layers buried deeply in the snowpack, resulting in very large avalanches. HIGH danger, with natural avalanches likely, is expected to develop this afternoon. Travel in avalanche terrain is not recommended. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1.5–2.5

    Southwest winds will be strong to extreme at all elevations, increasing throughout the day. New snow is being blown onto leeward terrain this morning. As more snow falls, winds will create large and sensitive drifts spanning whole start zones. Blowing snow and growing cornices will point to the most dangerous slopes. Stiff, textured drifts can fail naturally and break widely under ridgelines and on the sidewalls of gullies. Poor visibility will make it hard to assess the terrain above you. As snowfall rates and drifting increase, avoid steep wind-loaded terrain and the runouts of avalanche paths below. 

    (2/28/2024)

    Large natural wind slab avalanche that broke in a usually sheltered slope in the bottom of a drainage near Lundy Canyon. This likely ran 2/26.

    Photo: Clancy Nelson

  • Storm Slabs

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

    Snowfall rates of 1 to 2 inches per hour are forecast today, with higher rates by early evening. New snow will not have time to adjust and surface instabilities, both slab and sluff, will become increasingly likely - even in sheltered terrain below treeline. Steep slopes and terrain traps will become concerning as snow piles up. Road cuts, gully features, cliff bands, and mid-slope depressions are potential trigger points. As significant snow accumulates in mountain communities, be aware of overhead hazards from roofs and short steep slopes above confined areas.

    (2/4/2024)

    Shooting cracks. failure plane within the new snow

    Photo: Steve Mace

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3.5

    Snowpack depth and strength vary between drainages. Around Mammoth Lakes and areas to the north, the snowpack is over 5 feet deep. In the southern portion of the forecast area, the snowpack is closer to three feet deep. Several layers of sugary facets and crusts exist throughout the otherwise strong mid-pack. Depth hoar from the early season is still identifiable near the ground. These weak layers have shown improvements throughout February. However, with each major loading event, destructive avalanches have broken into old snow. 

    Hard slabs failing on these layers could involve the full depth and weight of the snowpack. Persistent slab avalanches can propagate long distances, connecting multiple start zones, and making for larger and more destructive avalanches that are difficult to avoid. The best way to manage this hazard today is to avoid large avalanche paths, including their runouts below treeline.

    Large persistent slab avalanches in Mammoth Rock Bowl and near the Poop Chute that failed naturally overnight on 2/4.

    Photo: Steve Mace

Avalanche Discussion

The winds have been strong since yesterday. Actual snowfall has underperformed the amounts forecast thus far creating large amounts of uncertainty. Precipitation is supposed to catch up this morning and intensify throughout the day, and into the overnight hours. Travel will become increasingly difficult. Natural avalanches will become increasingly likely and increasingly large. 

Destructive avalanches have broken into old snow with each major loading event this season. They may pose serious overhead hazards throughout this storm. If you decide to venture out today, don’t bet the farm as if you’re only dealing with new snow instabilities. 

Regions covered