Northwest Mountains

The avalanche danger is Considerable through most of the daylight hours, and could rise to High at upper elevations near or after sundown if we see the high end of snow forecasts.  New snow and strong winds are adding stress to a snowpack that produced a large natural cycle on Friday.  There have been numerous human-triggered avalanches in the past few days, including two large avalanches triggered yesterday near and above treeline (Schuylkill Ridge, Baldy).   Conservative terrain choices free of overhead hazards are essential today.  Lower elevations have been relatively quiet during recent loading events, and are a lower-risk option during today's storm.  

Even though the Special Avalanche Advisory for the busy holiday weekend has expired, the snowpack remains on edge, especially as we go into another loading event today.  Strengthening winds and additional snowfall could cause an uptick in natural activity today, on the heels of Friday's natural cycle centered around the Ruby Range.  If we see the high end of forecasted snowfall totals, we could see another natural cycle in the Northwest Mountains later today or tonight, and more natural activity migrating into the Southeast Mountains as well.  

Following a frenetic stretch of avalanche activity over the past few days, it’s worth taking a moment to highlight a few big-picture takeaways—and what they may mean for the rest of the season.

• Five people were caught in avalanches in the Elk Mountains on Friday, including two near Marble caught in large, potentially deadly slides (1, 2), and a snow safety worker caught while mitigating in closed terrain.  On Sunday, a skier escaped a large avalanche on Baldy after numerous skiers had put tracks on the exact slope on Saturday. Thankfully, we survived the weekend with no serious injuries or worse. Even our forecasters were surprised by how destructive and widespread Friday’s avalanche cycle became, given a somewhat modest loading event. A very large avalanche ran on Mt. Owen, while another D3 stretched up to a mile wide above Anthracite Creek. This has already been an unusual winter: a near-record slow start, unprecedented heat waves, extreme wind events, and warm, wet storms. We are dealing with a snowpack that is far from business-as-usual.  Unfortunately, surprise may be a recurring theme this season. Colorado snowpacks are always complex, and this one could prove to be especially tricky.
• Below treeline terrain has remained relatively quiet through several recent loading events. This is in part because of smaller snowfall amounts, but also because a Christmas rain event capped well-developed facets up to around 10,700 feet. This type of structure—a collapsible layer of weak snow beneath a crust—tends to be quiet until it fails dramatically once it finally crosses a difficult-to-predict tipping point. The rain crust thickness varies significantly with elevation and location, making for a more complicated setup that, once again, increases the chance of future surprises in our go-to terrain on storm days.  We could see those surprises during continued loading this week, or worse, later in the season once slabs grow significantly thicker.   
• Friday’s avalanche cycle was concentrated in the Northwest Mountains, with the largest and most impressive slides occurring along the Ruby Range. Historically, during gradual loading periods on well-developed weak layers, we often see the biggest avalanches start there before large activity eventually migrates downvalley as the season progresses and the snowpack deepens. Today, we're expanding the dangerous conditions to include the Southeast Mountains, where productive wind loading at higher elevations could bring the shallower zone more into play.  

Upcoming Events:  

Jan 6 Fireside Chat:  Expert Avalanche Panel at the Malardi Theater 5-7 pm

Jan 10 Trailhead Day: Snodgrass 10 am-2 pm

Jan 12 Fireside Chat:  Kim Grant from Silverton Mountain at Zuni West Brewing 5-7 pm