Snoqualmie Pass

Even though a storm will start to impact the Pass during the day, it shouldn’t bring enough new snow to build any real hazard before nightfall. Instead, you’ll find generally safe avalanche conditions with variable snow surfaces.

A change in the weather will bring windy conditions to the Pass Friday. Speeds should be plenty strong enough to move snow around. However, there just isn’t that much soft snow available for transport. While you may see some blowing snow and drifting at mid and upper elevations, we expect any newly forming slabs to be very small and isolated to exposed areas near ridge crest. 

Eventually, it will start raining/snowing during the day, but it should be too little too late in terms of developing an avalanche hazard. Any precipitation will only add to the blowing snow. As we move into the overnight hours Friday, that tune may change. As more snow falls, expect wind slabs to develop and the avalanches danger to increase. 

The more interesting conversation with this storm will be the old surfaces where snow accumulates. Thursday, an NWAC forecaster traveling in the Keechelus Ridge/Gold Creek area found a wide variety of snow surfaces. On southerly slopes, a strong melt-freeze crust was prevalent. However, as you shift to aspects that don’t receive direct sunshine, scoured icy slopes, breakable crusts, or soft powder were found. Many of these shaded areas harbored near surface facets (sugar) and surface hoar (feathers) over a crust. These observations from further east in the zone were similar to reports near the Pass proper and Alpental Valley. If these layers get buried, they could cause avalanches to trigger very easily. 

You can help us as we head into this snowy weekend. Send us an observation of what you find on the surface Friday morning, and if you see new snow burying any of these potentially weak grains. 

While our attention is generally on the new-old snow interface heading into this storm, we’ve also been watching the upper snowpack above the very stout and prominent MLK crust. You can still find several of the older interfaces in this ~2ft of snow. However, at the moment we don’t anticipate avalanches on these layers. Avalanche professionals and recreationists alike used the recent spell of nice weather and general stability to push deep into the zone and onto some of the bigger peaks. They typically reported low avalanche danger with minimal signs of unstable snow.