Soldier & Wood River Valley Mtns

Triggering a large avalanche remains possible in the eastern portion of this zone (the Little Wood drainage, southern Wood River Valley, Pioneer Mtns, and near Bald Mtn). There, the weak snowpack is still adjusting to the 16-20 inches of snow that fell last week. Avalanches can be triggered remotely—from flatter terrain below, above, or to the side of steeper slopes. Avalanches are most likely where fresh or recent wind drifts exist, but sheltered slopes are not guaranteed to be safe. Periods of direct or indirect sunshine could cause wet loose snow avalanches on very steep slopes. 

In all aspects of life, we sort the world into boxes to help us understand and communicate about the reality we encounter.  As avalanche forecasters, we use boxes known as avalanche problems to help describe the type of unstable snow that you might encounter in the backcountry. Different problems form in different areas and require different management strategies in order to avoid the hazard they pose. The avalanche danger is MODERATE in all of our zones today, but the avalanche problems and the hazard mitigation strategies are very different. 

In our northern areas, we are primarily dealing with a WIND SLAB problem right now. Avoiding the danger posed by a wind slab is relatively simple. (Notice the word "relatively" in there, we didn't just throw that in for fun. The backcountry environment is an incredibly complex one and we are well served to give it the respect it demands.) We can avoid wind slabs by avoiding terrain that is affected by the wind. No wind, no wind slab. If we want to cut things a bit closer, we can travel in terrain that is exposed to the wind, but where the wind has removed snow (scouring) instead of adding snow (loading). If we choose to cut our margins even closer, we can travel in terrain where the wind has been loading slopes with slabs and attempt to assess the stability of the wind slabs. Being able to do this successfully requires a great amount of experience and opens you up to high consequences if your assessment goes awry. 

In these same areas, even indirect sunshine may create WET LOOSE and DRY LOOSE avalanche problems today. The 8-12 inches of recent snowfall sits above a variety of crusts and other surfaces. It will not take much sunlight or heat to increase the cohesion in the new snow and make loose snow avalanches possible on very steep slopes. If the snow is getting "heavy", you could trigger small slides that have enough mass to push you around. A potentially bigger issue is natural slides striking you from above; loose snow avalanche problems can develop rapidly, so you need to move quickly and pay attention if you are traveling on or below steep avalanche paths. 

In the southeastern portion of our advisory area, we are currently dealing with a PERSISTENT SLAB problem. Persistent slabs are an entirely different beast to deal with than wind slabs. They form when weak, long-lived (hence "persistent") layers of snow are buried. As you just read, there are several options available when it comes to managing a wind slab problem. In contrast, a persistent slab problem presents a problem with few management strategies. Most of the time, the only real option you have is to avoid the terrain where the problem exists. We've spent many, many days in the backcountry, digging hundreds of snowpits and assessing snowpack stability. But even though the danger is "only" moderate in the Soldier and Wood River Valey zone right now, there are many slopes we wouldn't consider skiing or riding.  

Still with us here? When things are simple, the types of avalanche problems that you encounter in the backcountry feat neatly into the avalanche boxes. However, if you're old enough to be reading and understanding an avalanche forecast you probably know that the world we live in is rarely simple. The month of March has been dominated by alternating periods of snowfall and clear weather. Between storms, weak layers of snow formed at the snow surface and were subsequently buried by the next round of snowfall. In areas where wind slabs have formed on top of these weak layers, the wind slabs are adding additional stress to the weak snow underneath.

Are you facing a wind slab or persistent slab problem? We suspect you all have some extra free time today. Your challenge: spend some time thinking about what type of problem you might think of this as and how you might manage it. Call your favorite backcountry partner and ask them what they think. Today is a great day to open up your brain and learn something new. The backcountry environment always challenges us and provides us with endless opportunities to learn something new. Clear your brain of your preconceived notions and make an effort to look at this idea with fresh eyes. It is worth the time and effort.