Snoqualmie Pass

A return to stormy conditions on Sunday should have avalanche danger increasing throughout the day at Snoqualmie Pass. Steer around wind-deposited piles of snow and look for signs of unstable snow such as shooting cracks or whumpfing collapses as you travel. If you notice these signs or find there is more snow than you were anticipating, dial back your terrain choices.

This past week has seen Snoqualmie Pass receive multiple rounds of precipitation, creating a stout rain crust (12/9) with weak low-density snow sitting atop it. More snow in the forecast for Sunday should continue to add load on top of this crust, and there is some uncertainty around how the new snow will bond to the old snow surfaces. Dry Loose avalanches were stubborn to trigger but were running on the 12/9 crust the past few days in the zone on steeper slopes and we anticipate any avalanches on Sunday to be limited to snow sitting above the crust. A good public observation was given of a human-triggered Wind Slab on the north side of Chair Peak on Saturday and you should expect similar slab activity on Sunday.

Take the time and find yourself a nice test slope away from avalanche terrain so you can take a look at the new snow. If you find light and fluffy unconsolidated snow, you could be dealing with Dry Loose avalanches again on Sunday. If you find that the snow has consolidated into a slab, check the bond to the old snow surface and the crust to see how it reacts. If it is not well bonded to the crust or any number of inter-storm layers, be leery of slopes greater than 35 degrees. You can also measure the depth of the snow to see if more snow has fallen than you were expecting, thus increasing the hazard. Taking observations is a continuous process throughout the day since as conditions change, your hazard assessment needs to change with it. With the bulk of the precipitation set to fall during the day on Sunday, we expect the hazard should be increasing as the day progresses, demanding that you stay on top of how conditions are changing around you. 

Recent weather wreaked havoc on the snow around Snoqualmie leaving us with variable and potentially difficult travel conditions. Firm surfaces abound under the recent fresh snow. The snowpack at lower elevations eroded during the warm and wet weather amplifying early season conditions. New snow will help, but you will likely encounter numerous open creeks, downed logs, and exposed obstacles. Some of these obstacles will now be shallowly buried, so be cautious and give yourself extra time to deal with these demanding conditions.

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.