Bollettino valanghe

Eastside Region

Eastern Sierra Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

MODERATE avalanche danger exists at the Upper elevations. NW-W-S-SW-SE-E aspects will be of most concern for Wind slab from yesterday’s NE winds, shot of new snow (1-3”) and previous reserves of soft snow available for transport.  Today’s swing back to warm temperatures and increased solar gain will contribute to loosening of wind deposits on the sunnier aspects.  Check for signs of freshly wind loaded snow and be cognizant of warming aspects if you’re travelling in terrain that is confined or exposed from above.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Observations yesterday in the Mammoth and June areas found the ceiling for the NE winds to be around 9500ft mid-day with 2-4" of light new snow residing in sheltered terrain.  In contrast from around 2pm to midnight yesterday NE winds ramped up to sustained levels of 100+mph at Mammoth Mountain likely stripping the heck out of upper northerly aspects on the crest and depositing what snow was left in dynamic scope and area.   NW-W-S-SW-SE-E aspects in the upper elevations and especially in the northern part of the zone from Mammoth to June and beyond will be of most concern for potential wind slab and fresh deposits today. Of note, the high wind velocities late Tuesday may have also loaded isolated areas and extreme terrain at the middle elevations as well. Preceding yesterday's new snowfall, there was plenty of soft snow residing on northerly aspects ready to be harvested by the wind, and that surely took place in the alpine yesterday and overnight. Cold temperatures overnight and time will likely aid in locking in the snowpack, but conversely the fairly dramatic shift back to predicted sunny skies today and warm above-freezing temperatures could aid in loosening and destabilizing recent wind deposits. It will be a good day to take in the big picture of your complete route and pay attention to changing conditions especially in relation to heat, as well as looking for uneven snow surfaces and areas of heavy wind deposited snow, especially cross-loaded zones such as couloirs and gullies.

Avalanche Discussion

It will be a dramatic shift today back to warmer temperatures and solar gain, compared to yesterday’s raw day with most of the forecast zone staying below 20degF with cloudy skies and snow flurries throughout the day. It’s always a good idea to be heads up when the weather swings dramatically one way or another and today is one of those. Especially in the alpine with limited observations from Tuesday, investigate and take note of new wind slab, ribbons and pillows that formed during the NE winds. These may become destabilized by good solar input today and warming temperatures. Rimed cliff faces and complex terrain that has captured wind transported snow may start to shed debris as they warm back and will threaten terrain below… particularly on S-W facing aspects that are getting heated the most.

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RECENT OBSERVATIONS:

3/23 – Mammoth area – Sherwins –1-3” new snow

3/23 – June Lk area – Hemlock Ridge - 2+” new snow & NE winds

3/22 – Mammoth area – Sherwins –recent wind slab avalanche activity

3/22 – June Lk area – Carson Bowl – snow conditions

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