Bollettino valanghe

Eastside Region

Eastern Sierra Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Tue
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Small avalanches are possible in steep terrain. On leeward slopes below ridgelines and in gullies, watch for cracking in textured wind slabs. If you find wet snow in the afternoon, move to shady slopes to avoid sluffs coming down above you. Terrain traps and extreme terrain can magnify the consequences of triggering a small slide.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Temperatures are forecast to climb above freezing this afternoon. If warming meets or exceeds expectations, watch for rollerballs and small sluffs on solar aspects as the first sign that wet loose avalanches are becoming possible. Rocky chutes, vegetated slopes, and areas with shallow snow cover will warm first and most. Plan your day to be out from under very steep sunny slopes as the surface thaws. 

    (2/11/2023)

    Small wet loose avalanches in steep rocky terrain triggered old wind slabs. 

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1–1.5

    Drifts deposited over the past 48 hours are expected to be stubborn today. You'll still find them on the leeward sides of ridges, cross-loaded gullies, and downwind of convexities and trees. Look for rounded dunes with a textured surface, and cracking as clues that you’ve found wind slabs that could break around you. They’ll be most consequential in complex or extreme terrain where even a small avalanche can send you sliding over terrain traps or down steep slopes with a hard crust. Cornices are their own hazard. Especially if they break beneath you or tumble down the slope above you. A cornice fall may be the kind of trigger that initiates a larger wind slab avalanche. Limit your exposure to white waves looming over leeward slopes. 

    (2/12/2023)

    Cracking in small wind slabs

Avalanche Discussion

A few inches of new snow, along with strong and shifting winds deposited small but reactive wind slabs on multiple aspects over the weekend. Observers across the forecast area reported isolated cracking in drifted snow yesterday. Northeast winds were extreme in the Mammoth area and fresh drifts formed near treeline.

Aside from isolated wind slabs, the snow surface is variable and crusty in open terrain. Scoured slopes are covered in hard windboard and sculpted sastrugi. Melt-freeze crusts up to 2 inches thick have formed on solar aspects at all elevations. True east and west-facing slopes warmed for the first time last week and thin-breakable crusts cover open terrain. Sheltered areas still hold a few inches of soft snow.

Below the snow surface, layers buried in late January or early February mean it may still be possible to trigger an avalanche in areas where older slabs rest atop weak faceted snow or small surface hoar crystals. Though areas with this concerning structure are isolated in nature, they may still be reactive to human triggers. Feel for dense slabs sitting over thin windboard and sugary loose snow if you venture onto steep exposed terrain that faces north, northeast, or northwest. In sheltered terrain around the Mammoth area, patchy buried surface hoar has been reactive in snow pit tests. It can be hard to identify problem spots. You can play it safe by sticking to simple terrain or low slope angles. 

Temperatures warm rapidly today into the upper elevations causing some uncertainty over wet snow instability. Where melt-freeze crusts are thinnest, and where unconsolidated snow still exists, solar warming may thaw the surface enough for loose wet sluffs. Rollerballs and wet surface snow will be the changes to track if you travel on very steep sunny slopes. 

Regioni coperte