2018/2019 Snowpack and Avalanche Conditions Summary
Early November snowfall favored the Northern Mountains of Colorado. The snowpack in the north started to increase in depth as most of the Central and Southern Mountains stayed dry. Parts of the Northern Mountains were at 150% of median snow water equivalent while the San Juan Mountains and most of the Central Mountains were somewhere around 70%. While most of Colorado had weak snow layers near the ground, avalanche activity hit the Northern Mountains hard with 57 avalanches from November 1st to Thanksgiving Day. In comparison the rest of Colorado only reported 22 avalanches. (Click here to see a comparison of avalanche activity pre and post Thanksgiving)
The early snowfall in November resulted in an early spike in avalanche activity in the north. Although conditions were unstable for long periods in the early season, the Northern Mountains have gained significant snowpack depth and now have the most stable snowpack in the state. This doesn't mean you can't trigger avalanches in the north. Avalanches are in fact harder to trigger in this region but with the deeper snowpack depth avalanches can still be large and dangerous. Weak layers of faceted snow continue to strengthen but we will need this snowfall to continue for some time before we can say the snowpack has turned a corner to one with without worrisome, deeply buried weak layers. (Click here to see snowfall patterns pre-Thanksgiving)
Post Thanksgiving the weather pattern changed. A westerly and southwesterly flow started to bring copious amounts of snow to especially the Central Mountains. With all the new snow the Aspen and Gunnison zone saw a big spike in avalanche activity. This would be the first significant load on a weak snowpack in these two zones. Avalanches followed suit with 125 avalanches from Thanksgiving Day to present (12/8). It is too early to tell, but there is a chance that in some of the deeper snowpack areas of these zones, the snowpack could begin to strengthen. (Click here to see snowfall patterns from Thanksgiving to December 5th)
As we move to the Southern Mountains we see differences from the more northern neighbors. The south was very dry in November. I spoke to a forecaster in the San Juan Mountains on November 26th and this forecaster said, "Winter just began for us yesterday!". And the Southern Mountains did see some snow over the next 10 days. Though not quite the amounts that the Aspen and Gunnison zone saw. Even with the south picking up some decent snowfall in late-November and early-December, the snowpack remains weak in many places. Avalanche activity increased dramatically since Thanksgiving with 57 avalanches post-Thanksgiving compared to 4 avalanches pre-Thanksgiving. But still not near the quantity of avalanches in the Central Mountains. It could be that a big spike in avalanche activity is coming in the south with the next major load. The snowpack does not have the depth yet to have decreased temperature gradients and strengthening of weak layers. The next major snow storm in the Southern Mountains is expected to result in a significant avalanche cycle. (Click here to see the current snowpack situation in Colorado)
This is a basic synopsis of avalanche conditions past and present looking at snowfall trends and larger weather patterns. Stay up to date with day-to-day changes in avalanche conditions in your zone by checking your zone avalanche forecast daily.
