Northwest Mountains

You can trigger a slab avalanche where cohesive slabs rest above early-season weak layers.  The north half of the compass and some high-elevation southeasterly slopes are the most likely places to find a problem. Cracking and collapsing are clear signs of trouble, but don't count on these to alert you to danger.  If you encounter a slab above weak snow, steer towards lower-angle terrain to reduce your risk.  You can find safer terrain options on wind-sheltered southerly slopes, which often lack early-season weak layers.  Stay alert for warming snow, as minor wet avalanche issues develop on steep, southerly features.

The formula for a slab avalanche requires a weak layer and a slab above.  Weak snow from early in the season is common across both forecast zones on the northern half of the compass and some high-elevation sunny slopes.  When it comes to slab formation, there is a difference between the Northwest and Southeast Mountains forecast zones.  Increased snowfall in the Northwest Mountains over the past two weeks makes encountering strong over weak snow more likely.  Here, you can expect to find slab formation at all elevation bands and better connected through the terrain.  In the Southeast Mountains, less snowfall resulted in smaller, thinner slabs that cover less of the terrain.  For example, below treeline in the Southeast Mountains, you will likely find a shallow, weak snowpack that lacks a cohesive slab due to the faceting process, and at upper elevations, slab formation is often patterned by previous wind loading.  In both forecast zones, previous strong winds have played a significant role at upper elevations, leaving some slopes wind-loaded and deep, while others are scoured and shallow.

With each passing day, the snowpack becomes less reactive to human triggers as slabs weaken from the faceting process in sheltered areas and slowly adjust towards equilibrium in wind-drifted areas.  However, triggered avalanches remain an issue where you find cohesive slabs over weak layers, especially drifted features, where the potential avalanche size is the largest.  Thoughtfully investigate the snowpack as you travel to identify cohesive slabs and steer away from places that appear drifted or deeper than other terrain features.  The best-looking terrain for recreation, where the snow is often the deepest (north half of the compass or wind-loaded terrain), is the most probable place for you to trigger a slide.  Consider the consequences of being flushed down a steep slope into rocks or trees.

Warm weather continues to warm the snowpack on steep sunny slopes.  A few natural Wet Loose avalanches released on Thursday, so expect similar activity today.  Wet snow surfaces and roller balls can help clue you into the issue as it develops.  If you travel in steep sunny terrain, don't let this problem catch you off guard.