Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Rapid warming affecting recent storm snow will create areas of CONSIDERABLE avalanche danger today. Loose wet and wind slab avalanche problems are expected. Areas that did not undergo significant warming yesterday such as higher elevations or areas that spent most of yesterday under cloud cover will be particularly prone to avalanche activity. Identify and avoid areas of concern. Timing of travel in or below avalanche terrain will be critical for avoiding avalanche involvement.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Rapid warming conditions are expected to create areas of loose wet avalanche activity today on all aspects at all elevations. Most loose wet avalanches today will be human triggered, with natural avalanches possible in some areas. Avalanche size could range from small to large enough to bury a person.

    Avoid travel on or below steep slopes that are experiencing snow surface warming. Avoid steep slopes where roller ball activity is occurring. Backcountry travelers choosing to travel on steep sun affected slopes during the late morning and afternoon hours should expect to trigger avalanches.

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Ridgetop winds shifted from W to E yesterday evening. Overnight winds have been strong enough to create areas of blowing and drifting snow. Ridgetop winds today are expected out of the NE to E with ongoing strong gusts. Redistribution of recent storm snow is expected to have occurred in near treeline and above treeline areas. New wind slabs are expected on SE-S-SW-W-NW-N aspects. Some of these newly formed wind slabs could become increasingly unstable in response to rapid warming conditions. Avalanche size could range from small to large enough to bury a person.

    Identify the areas of most recent wind drifted snow, wind loading, and wind slab formation. Avoid steep slopes were newly formed wind slabs are likely to exist. Keep in mind the potential for instability enhanced by rapid warming as well as the potential for sun effects on northerly aspects from the higher sun angles this time of year.  

Avalanche Discussion

Observations were made yesterday on Lincoln Ridge (Yuba Pass area) and on Tamarack Peak (Mount Rose area). On Lincoln Ridge, rapid warming conditions were apparent by the mid morning hours. SE aspect test slopes started to show signs of wet snow instability by late morning. Colder NE aspects showed no signs of wind slab instability in this area. In contrast, colder conditions existed all day in the Tamarack Peak area with evidence of wind slab instability and no signs of significant snow surface warming.

Regions covered