Turnagain Pass

High pressure and mild temperatures continue to dominate much of our State.  This ‘lack of weather’ over the last week and a half has contributed to a stabilizing trend in the snowpack that has been afforded ample time to adjust to our most recent winter storm (March 10-14^th).

Specific hazards one may experience when travelling into the backcountry today include threatening cornices, wet loose avalanches late in the day, shallow wind slabs or an unlikely but very dangerous persistent slab.  Furthermore, surface conditions are quite variable throughout the backcountry right now.  Read here and here for a couple different accounts of a heinous fall (but positive outcome) a snowboarder took on Sunday in the Chugach range.

Cornices: 

Perhaps the most unpredictable problem today, we’ve seen evidence in the last week of natural cornice failure that have subsequently triggered slab avalanches.  This is the type of large trigger likely needed to wake up a persistent slab that could result in a large and destructive avalanche.  Your best mitigation tactic for cornices is to recognize them and limit exposure on top of or underneath these bulbous snow formations, particularly late in the day when solar input is greatest.

Wet loose avalanches: 

We saw evidence yesterday on the sunny side of Turnagain Pass where wet-loose avalanches or point-releases initiated and ran several hundred feet.  Though not a huge problem on their own, this is the type of small slide that can get you into big trouble if above a terrain trap or in complex, “no-fall” terrain.  It’ll be best to avoid steep, southerly aspects late in the day once you begin to notice the snow surface will no longer support your weight off your skis or sled.

Wind slab and persistent slabs:

Older wind slabs from last week may still be lurking in untested terrain today.  With people pushing further out into the periphery and skiing bigger, more committing lines over the last week the possibility of triggering an older, stiff wind slab exists. 

A note on persistent slabs:  The nature of this avalanche problem is persistent.  Though unlikely to trigger today, we know that weak snow layers do exist 2-5’ deep and a resulting persistent slab avalanche would likely be un-survivable.  To mitigate this problem, follow safe backcountry travel protocol that includes wearing and knowing how to use rescue gear and exposing only one person at a time on a given slope.