West Slopes South

A few inches of new snow at upper elevations won't be enough to drive much avalanche hazard. But if it gets wet from afternoon sunbreaks, you could see some rollerballs or pinwheels. Difficult travel conditions and natural hazards might be more problematic than avalanches.

Say goodbye to the warm, sunny weather that has baked the West South zone over the last week. Rain and high elevation snow are in the forecast for Friday night and Saturday. This change likely won't be enough to raise the avalanche hazard to Moderate, but there could be a few subtle changes that bear watching.

The new snow at upper elevations shouldn't be enough to drive much of a dry snow problem, but if we exceed storm predictions and it's windy, you could find a few drifts that fail easily over a crust. The more likely scenario is that the sun comes out in the afternoon and heats up the new storm snow, resulting in wet loose activity. Rollerballs, pinwheels, snow shedding from trees and rocks, or pushable snow on steep slopes may be more common than in recent days. Even if you get an avalanche moving, it likely won't be very big. But don't get caught by one near a terrain trap or pushed into exposed rocks.

We've been talking a fair amount about the overlap between general mountain hazards and avalanches during the spring. Snow clinging to rocky ledges and cliffs, sagging cornices, ice/serac falls, 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 occurrence. 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.

Due to overnight clouds, the surface may not be as firm in the morning as it has been in recent days. That should help minimize the slip-and-fall hazard. However, that may not be the case everywhere. The volcanoes are notorious for long fall accidents and may require an added sense of awareness. Bring the right equipment to travel safely over firm surfaces and know how to use it.

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. If you're traveling above roughly 7,000 feet, expect to find a more robust snowpack.