East Slopes South

Strong E winds loaded unusual aspects this week, especially at upper elevations and near the Cascade crest. On high shaded slopes near ridgelines, use caution near areas of firm or hollow sounding snow. Warmth and sunshine will also be a major factor on Friday. Stay off of slopes with wet, sticky snow during the middle of the day.

Over the past several days, a strong temperature inversion combined with multiple freezing levels, and strong easterly flow are all factors that indicate snowpack variability can be expected by aspects, elevation, and even slope to slope. Thursday saw a switch to mild westerly wind, which allowed warming temperatures to reach the east slopes of the Cascades with temperatures rising above freezing in most locations. 

Very strong winds built shallow but reactive wind slabs Monday. Reports from Tuesday and Wednesday suggest that winds were strong enough to redistribute the snow into a patchwork of small wind slabs rather than thicken existing wind slabs. Wednesday, the east wind continued to keep the snow surface cool and wind transport active despite above freezing air temperatures, so shallow recently formed wind slabs may exist at upper elevations. Use visual clues to identify areas where wind slabs may exist such as slopes directly below cornices, pillow-like drifts, and convex slopes or gullies. Use caution where you see evidence of freshly wind transported snow and navigate around wind-loaded features especially where slopes are greater than 35 degrees.

East winds have kept snow surfaces cool and prevented the possibility of loose wet avalanches despite the sunny weather through Wednesday. We expect that the shift to warmer temperatures Thursday released some loose wet avalanche activity, but may have been limited by cloud cover. Sheltered slopes still holding fresh snow are the most likely to experience loose wet avalanches on Friday. Firm and scoured snow surfaces will likely not warm rapidly enough for loose wet avalanches to be a concern. Let the behavior of the snow surface guide your decision making more than the thermometer. Watch for signs of the snow becoming "heavy" and roller balls or pinwheels forming on the surface. This is evidence that you could trigger a loose wet avalanche. Steer away from slopes in direct sun which are steeper than 35 degrees if you see signs of warming surface snow.

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.