Snoqualmie Pass

Wednesday’s change in the weather should result in generally safe avalanche conditions at Snoqualmie Pass. If a convergence zone delivers higher than expected snow totals, you could find some wind-drifted pockets to steer around at upper elevations by day’s end.

Springlike weather has dominated the Snoqualmie Pass zone for the past several days, resulting in recurring wet avalanche concerns. Glide activity, cornice failures, and Wet Loose avalanches were all observed in the zone recently and the remnants from this cycle are easy to spot. As Wednesday’s weather rolls back to something more closely resembling winter, wet avalanche activity should start to taper but may not be fully eliminated. 

Temperatures are expected to drop and we should see some snow falling from the sky by mid-morning. New snow will be falling on variable surfaces created by the wet cycle and is expected to bond fairly well.  Storm totals may depend on when and if a convergence zone sets up over the pass, but generally speaking we aren’t anticipating enough new snow to create a widespread dry avalanche problem on Wednesday. That said, if you’re going to find a dry avalanche, it will likely be in the form of shallow Wind Slabs building at upper elevations by day’s end. Even if you find one of these pillow-like piles of snow, they shouldn’t be large enough to be very consequential unless you get swept off your feet near a terrain trap such as cliffs or trees. With continued snowfall delivered by the convergence zone on Wednesday night, we may be closer to Moderate danger on Thursday. 

Any new snow that falls during this event will only become fuel for later wet avalanches once we return to warmer and sunnier springtime weather. This time of year, it may not take much to start that process. So if the convergence zone doesn’t materialize and the sun comes out in the afternoon, look for any new snow to start to rollerball as it “ripens up” and becomes capable of producing Wet Loose avalanches.  Other than that, we are still keeping an eye on the 3/8 facets above the Early March Crust to see if it will awaken later this spring. Although this layer is highly unlikely to be an issue on Wednesday. 

Lower elevations have been through multiple rounds of warm temperatures and rain, resulting in exposed natural hazards such as rocks, stumps, open creeks, and bare ground. This storm could deliver some snow to these elevations, but more likely will be a rain/snow mix, which will further exacerbate many of these travel concerns.