Snoqualmie Pass

A pattern change from warm and sunny to cool and snowy is expected on Monday. The cool weather should help firm up and stabilize the current surface, creating difficult travel conditions and a good sliding surface for the incoming snow. There may not be enough accumulation to drive widespread avalanche danger, but that doesn’t mean there is no danger.

Monday should bring a return to snow showers at Snoqualmie Pass as we transition away from warm and sunny weather. We are not expecting enough accumulation to drive much of an avalanche hazard, but that doesn’t mean that hazard doesn’t exist. Here are a few things to keep in mind if you’re out and about in the mountains:

• The current snow surface is variable and in many locations firm. Unlike this past weekend, the sun will not be softening surfaces as the day wears on. Difficult travel conditions may persist throughout the day, even with the new snow. Take it slow and be sure you have the proper equipment and travel plan to minimize your risk of taking a long and uncontrolled fall.
• The new snow may not be well bonded to the current variety of snow surfaces, so you could find that it is easily triggered and running far and fast on a firm crust. Use quick hand pits or test slopes to see how the snow is bonded and reacting to your weight.
• Gusty winds could create some deeper and possibly more sensitive piles at mid to upper elevations. These piles are more likely to develop on the leeward side of ridgelines, in confined chutes, or at the base of cliffs. If you see one of these smooth pillow-like piles of snow, consider steering around it.
• The amount of snow involved in any potential avalanche may not be enough to bury you, but be sure you’re not swept off your feet or caught off guard on consequential slopes or near terrain traps. Remember that avalanches are often easier to trigger on steep features over 35 degrees, including convex rollovers. Obviously, if more snow is falling from the sky than we are anticipating, recognize that avalanche hazard is increasing.
• The recent warm and sunny weather re-exposed rocks, creeks, and other early-season natural hazards. It will take more than this storm to fully bury them again, so be careful not to get caught by one of these objects.
• At the lowest elevations, there may be a period of rain or mixed precipitation. This includes areas west of the pass. The rain should not drive much in the way of avalanches, but you could find a few rollerballs and pinwheels in isolated areas.

We will continue to monitor the weak snow near the Late January Crust as a thicker slab develops above it over the coming weeks. This layer should not come into play during this storm. Above it, you will find a generally strong upper snowpack of settled storm snow and multiple melt-freeze crusts of varying thicknesses, including the current surface.