The Bottom Line:

Moderate to strong winds out of either side of South have formed tender wind slabs on lee aspects and cross loaded terrain features in exposed areas 1-4’ deep.  North can be easier to identify wind loaded characteristics.  It is the sneaky corner pockets or specific features on NW/W and NE/E to be mindful of.  Avoid steep, complex and possibly challenging terrain that is rocky or thin coverage.  Poor visibility will limit travel, but also keep those freshly sculpted cornices on check as well.  Always give respect and wide margins.  Speaking of… that was a significant storm with critical red flags.  However, no notable natural avalanche cycle?  Small steps and lots of data is vital for decision making.

The old snow surfaces (bed surface) for winds slabs or settling snow to run on include: rough, smooth, ice, melt-freeze crusts, sun crusts, sastrugi, wind slab and 4-8″ of weak snow. A prior knowledge of where/how these surfaces formed are highly dependent on aspect and elevation.

Any surface avalanches within the new snow could step down to one or more Deep Persistent weak layers and cause a very wide and deadly avalanche. Consequences remain high. Give runout zones a wide berth. Human triggered avalanches are likely and natural avalanches are still possible.

Snow levels reached up to 2500′ over the last 24 hours. Below that level, especially less than 1500′ there was a lot of rain-on-snow. Wet slabs and large wet-loose avalanches are likely today below 2000ft, especially in open terrain steeper than 32 degrees and on South aspects. 

Wet avalanches can be very destructive and trigger slab avalanches that break into deeper snow. Wet avalanches include point-releaseavalanches or sluffs.  Monitor the snowpack surface, and move to colder, shadier slopes once slush layers form.

Recent heavy snowfall and strong warming is stressing the remaining persistent weak layers deeper down in the snowpack. The result is an increased likelihood of very large and deadly avalanches that can break very wide across a slope.

When seeking out wind protected zones, remember that wind-protected pockets may be harboring buried surface hoar layers. Protected means preserved.

Buried Surface Hoar Layers (These layers have become less reactive in snowpits, but smaller slides could still step down and trigger them):

• Jan 25th melt freeze crust is about 3-4 feet deep (with recent winds and snow, there is a lot of variability on depth of this widespread layer) sitting on top of it are near surface facets, and buried surface hoar from Feb 1-4.
• January 10th surface hoar is now buried about 4-5 feet deep
   

Old Melt Layers and Crusts:

• Dec 31 surface hoar layer is present in the Transitional and Pass zones, about 5 ft deep. This layer caused some natural avalanches in early January.
• A buried persistent weak layer about 8+ feet deep (The “Big Warmup” Layer, Formed Nov 17th) is still a concern. Numerous natural avalanches observed 1/27 likely on this layer.
• A wide safety margin is necessary. This setup could produce avalanches that break wider than expected, and are most likely to be triggered from shallow trigger points like rocks or small trees. You could ride the same slope numerous times until that right spot produces a large destructive slide.

Pit at Flower Mountain, 2700’, East aspect on Mar 15 (now has an additional 2ft on top). PST 60/100 End on the Jan 10 buried SH 4-6mm that is rounding down 130 cm

Depth Hoar at the Ground (In thinner areas above 3,000′):

• October snow followed by long cold snaps created depth hoar at the ground in most areas.
• You are most likely to human-trigger this layer from shallow spots around rocks, or trees, or have a surface avalanche step down to the ground on this layer. Any slides that break to the ground are likely to be deadly.