Bollettino valanghe

Mount Shasta

Mount Shasta Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

Added snowfall and strong west and southwest winds have increased the possibility of triggering a wind slab on NW-N-NE-E-SE aspects near and above treeline. Heightened avalanche danger exists on leeward slopes beneath terrain features that promote drifting. Avoid traveling in steep terrain experiencing active wind loading that host wind effected or lens-shaped surfaces to best reduce your risk.  

Problemi valanghivi

  • Wind Slabs

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

    Trickles of snow accompanied by strong west and southwest winds have been a consistent theme in the mountains over the last 72 hours. This occurrence has led to large amounts of snow being transported and deposited onto leeward NW-N-NE-E-SE catchment zones. North aspects, especially in the alpine, hold the greatest concern, as these areas have been subjected to the highest rates of wind loading and will hold the largest and most sensitive slabs. Today, smaller, recently formed drifts may be more present and easier to identify. However, the potential of a much larger and consequential wind slab, which may give no warning signs, remains a risk.    This problem will become more present as you gain elevation. Identify areas of concern by dialing in your mental radar to features that promote drifting, like ridgelines, cliff bands, alpine ribs, and convex break-overs. Use wind lips and cornices to orient yourself to slopes that have experienced wind loading, and assess for slab characteristics within the snow by digging a pit or using inconsequential test slopes.  

Avalanche Discussion

Wind effected surfaces are widespread near and above treeline, and it may be difficult to discern where a wind slab exists. So, ask yourself, am I on a leeward aspect beneath a terrain feature that promotes drifting? Have I observed any sings of instability, like surface cracking? Does this snow show signs of wind effect? Is the snow a cohesive slab? Where would the likely trigger point be? What's the best way to keep mitigate the risk? 

Yesterday, forecasters observed snow conditions in the Old Ski Bowl and Avalanche Gulch. The findings of wind slabs were few, but the signs of wind effect were plentiful. Furthermore, a crust combo was discovered 30 cm (12”) down, that formed during the warm-up on March 6th–8th. Stability tests revealed the snow sandwiched in between the two crusts to be reactive and hold clean propagation. While not a major concern as of now, these crusts hold the potential to be a problematic weak layer in the snowpack. These crusts hold varying thicknesses and distributions and were observed to be easily penetrable on southern aspects, opposed to east and north aspects. 

The Everitt Memorial Highway is OPEN. Castle Lake road is still closed.

Regioni coperte