An Avalanche Watch is in effect for the San Juan Mountains till 0800 Wednesday. An incoming storm system brings warm, moist Pacific air into Southwest Colorado and potentially significant snowfall. Snow looks to develop overnight Tuesday and continue throughout the day on Wednesday. If snow totals verify or exceed forecasted numbers, we could see very dangerous avalanche conditions develop by early Wednesday morning.
Today is a transition day before avalanche conditions change. Triggering a large and dangerous avalanche has become more difficult since our last major loading event eight days ago. Low-density snowfall over the past couple days did not provide a large enough load to wake up buried weak layers and produce widespread avalanches. These problematic layers are getting buried deeper and slabs are settling and stiffening. This makes it more difficult for a person or machine to impact weak layers buried deep in the snowpack. On some slopes, weak November facets are showing signs of strengthening. On other, shallower slopes these weak layers continue to persist and still produce propagating results in stability test. Free information highlighting unstable snow such as cracking, whumpfing collapses, and recent avalanches are not as obvious from even a few days ago, but still exist.
These current conditions place us in that unspoken but spoken about avalanche condition known to many snow and avalanche professionals as “scary moderate”. The slope you choose to ride or ski may or may not avalanche. It is really hard to say, but very much possible. The widespread nature of our persistent weak layers makes backcountry travel complex. You can steer clear of wind-loaded slopes or steep, open convexities to reduce your avalanche risk. These wind-drifted areas are still capable of producing larger, more dangerous avalanches and spreaing over multiple terrain features.
The upcoming storm has potential to provide a heavy and quick shock load to the snowpack. Our weak and fragile snowpack has been very reactive producing numerous natural and human-triggered avalanches during and after each major loading event since early December. You should expect more of the same with our next storm. It is exciting to see consistent snowfall this winter after such a warm and dry winter last year. However, you should recognize our snowpack is still scary and unpredictable. The snowpack in the San Juan Mountains is different than the past several years. Take this into account when you travel in the backcountry and realize that slopes you may have ridden many times last season or the season before may no longer be safe to blindly jump on.