East Slopes South

Wind slabs will be increasingly stubborn, but you can still trigger them on steep upper-elevation slopes in the lee of ridgelines.  Avoid slopes below cornices and lense-shaped pillows, particularly on polar aspects where slabs are slower to heal. On steep,  sun-exposed slopes, warming temperatures may destabilize the recent storm snow to  create roller-balls and  small, but potentially harmful loose wet avalanches. 

The East South snowpack is far above average for this time of year with mid-elevation snowpacks in the 20-30" range, with over 40" just to the west of this zone at White Pass. After our initial snowfall, a rain event and warm period built a supportable rain crust on November 16th. This has served to lock in the base of the snowpack and batter down vegetation creating surprisingly good travel conditions and snow coverage for November.  Snow that fell last week is generally well bonded to the 11/16 rain crust and no significant avalanche activity was observed in the recent snow.  Friday and Saturday (11/20-21) brought sunny, calm, and warm conditions. The snow surface stabilized as a crust formed on solar aspects and at lower elevations. Higher elevation and shaded slopes largely escaped the melt cycle and good travel conditions were found on these slopes throughout the weekend. Winds accompanied a storm arriving Tuesday night, which brought 2-6" of snow through Wendnesday.

Expect to find wind slabs near and above treeline on lee slopes. Warmer temperatures and sunshine may start helping to hasten the healing process, however potentially larger wind slabs will be slower to heal at higher elevations where winds have been persistent since Monday and on NW-N-NE-E aspects which have not experienced much direct sunshine.  Look for signs of recent wind transport s and cornice development to clue you into where slabs might have formed. Stay alert for firm and textured snow surfaces and cracking in the snow as you travel as evidence that you could trigger a wind slab.  When in doubt, choose lower angle terrain (less than 35 degrees) and navigate away from features such as cornices and convex rolls.  

On Thursday afternoon, temperatures warmed to just above freezing at sites from 4500-5900 ft in the East South zone. With mid-day sunny periods and roller-ball activity OBSERVED on Thursday at White Pass, we expect it was sunnier with more of this activity in the East South zone.

Freezing levels may rise to around 8000-9000 ft on Friday, with plenty of sunshine likely through early afternoon before clouds roll in and the wind picks up into the moderate range.  Pay careful attention to slopes above and around you as the warm temperatures and direct sunshine warm snow surfaces. Roller-balls are precursors to loose wet avalanches which can entrain the recent snow. Adjust your aspect to cooler, shaded slopes if you find wet snow you can sink in past your ankles. If you're caught in a small slide, expect higher chances of trauma given the early season snowpack.

Despite the great start to our winter snowpack, keep early season conditions in mind. Rocks, stumps, and vegetation may be barely covered and many creeks are open.

Now is a great time to run through your safety equipment and make sure everything is in good working order. CLICK HERE for more information on early-season equipment checks. What did you see out in the field? SHARE YOUR OBSERVATIONS with NWAC and the backcountry community. Check out this BLOG POST and VIDEO TUTORIAL to find out more about why observations are so important and how you can view and share information on NWAC’s new public observations platform.

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