Silver Valley & Bitterroot Mountains

Dangerous slabs of snow are teetering above and overloading fragile weak snow layers directly below. Plenty of snowpack red flags are fluttering in the breeze for you to trigger a large and deadly avalanche. Avalanches on drifted slopes are more likely to break wide across terrain features and travel farther than you expect. With the complex array of collapsible snow layers underneath the new snow, avoidance remains the best tool in the bag.

Fresh, cohesive slabs teetering above a pile of large (1-1.5 mm) faceted grains and very large surface hoar (15 to 25 mm) is like rolling the dice with a loaded gun. It won’t take much effort to trigger a large, dangerous avalanche on slopes steeper than about 30 degrees. Now that the main loading period is behind us, we move into a more incremental loading pattern. These periods are more challenging to track the slow upward progression of the snowpack sensitivity needle, and often require a higher level of patience and not walking the line with slim safety margins.

Observations from the last two days report reactive borderline touchy conditions – natural avalanches triggered by falling cornice chunks, snowpack tests failing with isolation or easy force, and riders easily triggering steeper convex rolls and cut banks with ski pressure. Subtle cracking along the skin track transition to long-running cracks in drifted areas, and loud rumbling collapses are being reported where surface hoar is upright and intact below. The snowpack appears to be providing us with the most feedback of dangerous conditions we’ve seen so far this season. The million-dollar questions to ask ourselves is with such dense snow sitting over such soft snow, why did some slopes not avalanche?

Snow doesn’t like or handle rapid change well, and building two-foot-thick slabs in just over 24 hours will effectively push the snowpack scale to the edge – if not over. With how weak (mostly F to 4F-) the snow is below the new snow, the odds of triggering a slide on an adjacent slope or from below is exponentially increased. Add a patchwork of old, wind-affected layers and crust, and you’ve got a complex, unpredictable upper snowpack with many flavors of potential doom. Avoid traveling above terrain traps like gullies or depressions with steep overhead hazards – especially where there is no exit option.

While tough, adjusting our travel mindset from what is has been over the last several weeks will go a long way to help reduce your avalanche risk. The usual risk management strategies should not be relied on during these elevated moments. The overall size and weakness of the persistent grains below the new snow is atypical for what we’re usually dealing with this time of year across North Idaho. Don’t rely on stability tests as a go or no-go decision, and treat early warning signs of fresh avalanches, cracking in the snow, and loud audible collapses as your backcountry guardian angel.

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**We continue to receive intermittent reports of opening glide cracks and some failing naturally producing large to very large glide avalanches. Avoid traveling on or below slopes where a glide crack has opened. These types of avalanches are difficult to forecast when they will release.**