Snoqualmie Pass

Say goodbye to our warm and sunny weather. Rain is expected to fall on the tops of most mountain peaks. Although snow shedding from rocky features can never be ruled out this time of year, you're more likely to encounter general mountain hazards and tricky travel conditions.

A pattern change is on our doorstep at Snoqualmie Pass. After a week of sunny, warm weather baked our snowpack and had us all thinking it was May or even June, we're heading back to typical April weather. Clouds should thicken, and rain will fall to the top of our peaks. Maybe on the highest slopes a dusting of snow will fall. 

We don't expect this storm to significantly change avalanche potential, but some subtle changes could come into play on Saturday.

Cloudy conditions overnight may prevent the surface from freezing as solidly as it has in recent days. With the added rain, you could find that there is more soft snow available to push a small wet loose avalanche on steep, snow-covered slopes. However, you should still bring the right equipment to travel safely over firm surfaces and know how to use it. Slip-and-fall accidents are common throughout the spring.

We've been talking a fair amount about the overlap between general mountain hazards and avalanches during the spring. Snow clinging to rocky outcrops and cliffs, sagging cornices, and even rockfall are common this time of year as the mountains shed their winter coat. Some blocks of snow will melt in place, while others will shed from rocky ledges as a single unit. The rain could help grease some of these blocks, increasing the likelihood that they will fail in a glide-type occurence. These isolated events are impossible to predict, but you may want to make travel plans with these low-likelihood, potentially high-consequence hazards in mind.

Snow coverage varies greatly with aspect and elevation. Open holes and creeks, thin snow bridges, and exposed ground or rocks are commonplace throughout the hills and will likely become more widespread after the rain. Maybe these aren't much of a problem if you're walking/hiking, but if you're planning to ride a sled or ski, you'll undoubtedly encounter longer travel times than you're used to.