Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
View on map

Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Open full map
Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The storm has left us with a dangerous setup of dense slabs several feet thick over a widespread weak layer.  On slopes that didn't recently avalanche, slabs are reactive to human triggers, and there is potential for more natural avalanches today with additional snow and windloading.   Careful snowpack and terrain evaluation are essential.   The danger could rise to HIGH again later today or tomorrow.  

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–3

    The recent storm formed slabs 2 to 4 feet thick, overloading the widespread facets and faceted crusts that formed during our long December drought.  These avalanches can propagate hundreds of feet wide and have been remotely triggered from thousands of feet away. This is a very challenging problem to manage; give yourself a wide margin for error when traveling near or below slopes steeper than 30 degrees.  Large avalanches could run naturally later today and tonight as more new and windblown snow accumulates.  

    A widely propagating persistent slab avalanche on the east face of Gothic Peak ran naturally around 1/15.  

Avalanche Discussion

Good visibility yesterday allowed us to verify a widespread natural cycle occurred over the holiday weekend, effectively reducing the avalanche hazard on the many terrain features that recently avalanched.  Furthermore, field observations suggested a decreasing sensitivity more in line with Considerable (Level 3) danger, so the Avalanche Warning was canceled yesterday afternoon.  Coming off of a 36-hour pause in loading, the relatively modest loading before sundown is expected to increase the danger but keep us at Considerable through the daylight hours.   The danger trend overnight into tomorrow is tricker, with more snow and windloading bringing the hazard back to, or potentially over the line to High danger (Level 4) conditions again.  We'll re-evaluate tomorrow morning depending on how the storm and field observations shake out today. 

Storm totals over our well-developed drought layers range from 42" (3.75" SWE) at CBMR to 83" (6" SWE) at Irwin.  The bulk of this loading came in during the MLK weekend slammer. Our entire forecast team was out yesterday scrambling to document patterns in avalanche activity before this next storm arrives.  You can check out photos of recent avalanche activity and look at those patterns on our avalanche visualizations page, along with some highlights in this video.  Persistent slabs have occurred on all aspects and elevations. In the last few days the majority of avalanches were D2 or larger, with a few alpine slopes producing D3 avalanches.  For example, the east face of Gothic reached Gothic Road, and there were several house-smasher sized avalanches in the Ruby Range.  Even if you're traveling below treeline, the slab size is not something to take lightly: slabs are generally 2 to 3 feet thick and settling into denser, stiffer slabs that will propagate wider but give fewer signs of instability.  There are some options to reduce your risk now:  recent bed surfaces, wind-eroded slopes, and on some low elevation, sunbaked slopes in the shallow zone, slabs accumulated on mostly bare ground.  These slopes don't offer the most appealing riding conditions today; thus, patience and avoidance are still the name of the game for steep and attractive-looking slopes.  Slope angles less than 30 degrees that don't connect to steeper slopes above you are the most reliable way to manage today's dangerous snowpack.  

Regions covered