Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
View on map

Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

While the small amount of snow expected today should not form new avalanche problems, hard slabs of wind drifted snow formed by the intense NE winds still exist in many near and above treeline areas. Human-triggered avalanches remain possible. In near and above treeline terrain the avalanche danger is MODERATE today with LOW danger below treeline.

Avalanche problems

  • Wind Slabs

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

    Today's new snow amounts should remain too small to form new wind slabs. However, hard slabs of wind drifted snow still exist on slopes loaded by the intense NE winds from earlier this week. These mostly formed on the NW-W-SW-S-SE aspects in near and above treeline terrain. The N-NE-E aspects hold very scoured surfaces. Triggering one of the stubborn hard slabs has become more difficult, but if they do fail they could break above the person who triggers them. These wind slabs may be easier to trigger where the hard slab is thinner or in more complex terrain like couloirs, hanging snowfields, cliffy areas, unsupported slopes, and steep convex rollovers.

    Smooth areas of drifted snow, firm hollow-sounding snow, ripples on the snow surface, and other wind-created features can all help identify where these hard wind slabs may exist. The variability in thickness, strength, and distribution of these hard slabs makes evaluating them challenging. Avoiding wind-loaded slopes in favor of more sheltered slopes can reduce potential exposure to the wind slab problem. 

Avalanche Discussion

* Observers have reported hard wind slabs on slopes loaded by the NE winds. These wind slabs vary in thickness from a few inches up to 2+ ft. Yesterday, Some of these exhibited signs of instability like whumpfing and cracking, and others did not. Some snowpit tests on these hard slabs produced unstable results, and others did not. 

* Wind scoured and sculpted surfaces are widespread across the forecast area. N-NE-E aspects are especially scoured. Wind-affected snow surfaces exist at all elevations and in traditionally sheltered areas.

Regions covered