East Slopes South

Conditions remain dangerous at upper elevations five days out from a major storm cycle. Very large deep slab avalanches have continued from upper-elevation start zones in adjacent zones, so think twice before going in or underneath big steep slopes while the snowpack adjusts to a heavy new load. Cornices or smaller avalanches you trigger can step down to produce a very destructive avalanche.

Very large, deep slab avalanches released each day since last week through Monday in the southern and central Cascades. Monday was several days removed from a major storm cycle and a very large natural avalanche occurred on Chair Peak at Snoqualmie Pass (NE-E-SE 5800; HS-N-D3.5/R4-O). At the boundary of the East South zone, observers just east of White Pass saw evidence of large avalanches that released last week.  Deep and large natural avalanches were observed in the Crystal backcountry over the weekend. The avalanches east of White Pass were not as deep or widespread as those in Crystal or in the Central Washington Cascades.  We still have plenty of uncertainty about deeper weaker layers, but we have every reason to believe they remain in the Cascades East South snowpack. The continued chances for more of these avalanches should determine where and how you travel on Wednesday. Avoid going in or underneath steep slopes, especially recently wind-loaded areas above 5,000ft. Cornices are big in some areas, avoid going underneath these because if they fall they could trigger very large avalanches. 

Wind slabs linger at upper elevations on Wednesday. If you trigger an avalanche in the upper foot or two of snow, it could be large or even step down to become a very deep and destructive avalanche. Wind slabs were found above buried surface hoar in the adjecent Cascades East Central zone. Given the potential for more reactive wind slabs and the potential for deep slab avalanches, you should avoid large avalanche starting zones, especially at mid and upper elevations. Avoid recently wind-loaded, leeward slopes 35 degrees and steeper.  Stick to lower angled and well-supported slopes and features.

A large to very large wet loose avalanche was triggered by what appeared to be cornice fall on Spiral Butte, just east of White Pass on Monday. With more mild temperatures and sunshine expected on Wednesday, wet avalanches could entrain deeply to become quite destructive.  At lower elevations, choose slopes less than 35 degrees and once again avoid exposure steep slopes or corniced ridgelines above you.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.