Aspect: Wind loaded aspects and features N-NW-W – Specific distribution.

Elevation: Alpine

Uncertainty: Moderate

We received 8″ to 12″ of  snow in this zone over the last few days with moderate to strong winds out of the South/SouthEast.

This snow came in cold, dry, and loose.  There was surface snow available for wind transport. Natural avalanches are possible and human triggered avalanches are likely. Wind slabs are expected to be reactive.

Yesterday the winds began to decrease and at some point today they will switch Northerly.  Winds slabs will still need time to heal so be patient and vigilant.

Look for signs of wind loading that include: cracking, collapsing, shooting cracks, hallow sounds, and strong over weak layering. Avoid wind loaded aspects and features.

Beware of  terrain traps (e.g. gully, rocks, dense timber, cliff, crevasse) or areas where snow could pile up quickly. Avoid traveling above or below terrain traps.

Aspect: All aspects – Widespread distribution.

Elevation: Tree-line and above

With 8-12″ of new snow (+ a bit of wind transport) that could be sitting on weaker layer from the pervious surface (Near Surface Facets), reactive to stubborn storm slabs still could be lingering out there.

Observations from Old Faithful last Sunday found a thin crust with weak snow down 60-70cm near 3,200′ and below. This bathtub ring effect, from lower-elevations to mid-elevation, where freezing levels are more likely to cause crusts and weak layers – should be carefully evaluated. Also, of note was surface hoar formation 12/8-12/9 that could be buried by the incoming snowfall and overloaded by wind slab.

Weak facets at the bottom of the alpine snowpack in both zones, and the potential of lingering October Rain Crust with weak layers above and below have not seen a significant avalanche cycle. However, it is possible that any surface avalanches could step down to the deeper layers, or even the ground in certain shallow areas in the alpine. 

• One of the best ways to reduce your exposure to deep persistent weak layers would be to stick to areas of deeper snowpack (>1m deep). But be wary of hidden rocks that can act as trigger points, and thin areas around the margins of a slab.
• Manage the terrain by only exposing one person at a time to the hazard, use group up spots out of harms way, and carry radios for communication.
• Look and listen for deep whumping! Report any natural avalanche activity on these deeper layers!