Lawinenlagebericht

Northwest Mountains

Crested Butte Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Tue
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

These early season conditions are difficult to manage. The terrain with the most snow to ski and ride, is generally located near and above 11,000ft on northerly to easterly aspects. However, that same terrain is also the most dangerous with many natural avalanches having occurred and multiple close calls with human-triggered avalanches. You can find less avalanche risk on southerly-facing slopes and terrain below 10,500ft, but it is much more difficult to find enough snow to ride in those areas. If you choose to travel in problematic areas, select simple terrain with lower slope angles that are not connected to steeper slopes above, or be prepared to be added to the avalanche accident statistics. 

 

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    You will find a fragile base to the snowpack on northerly and easterly aspects from the early seasonal snowfall back in October.  Over the past week, up to 2 feet of snow has fallen on top of these Persistent Weak Layers.  Observations from the weekend included natural avalanches, collapses, shooting cracks, remotely-triggered avalanches, and an unintentional skier-triggered avalanche.  The evidence seems pretty clear that triggered avalanches remain likely on northerly to easterly aspects above 10,500ft. This problem is best managed through selection, avoidance, and/or conservative slope angle.

    This persistent slab avalanche was remotely triggered from below on Purple Ridge. 11/26

Avalanche Discussion

Over the weekend there were two close calls with human-triggered avalanches. On Purple Ridge in the upper Slate River Valley, a group of skiers remotely triggered a large avalanche from a low-angled slope below. While over the hill in Marble, the third skier to enter a slope triggered a large avalanche and became partially buried. That same avalanche further partially buried their two partners that descended before them. We have further documented many natural avalanches that also ran over the weekend. The conundrum of finding enough snow to ski or ride, but not getting caught in an avalanche, is making for difficult conditions to manage.  

Looking at our avalanche database, the vast majority of the avalanche activity has occurred on northerly to easterly-facing slopes, near and above 11,000ft. This terrain is highlighted by the persistent slab avalanche problem. On southerly-facing slopes, we have observed a number of small storm or wind slab avalanches that ran on Saturday during a period of elevated westerly to northerly winds. Observers traveling on southerly-facing slopes yesterday found those previous wind drifts to already be stubborn or unreactive to triggering. If you are traveling on higher southerly-facing slopes today, you can mostly expect normal caution while continuing to manage wind-loaded terrain features for any outliers that could still produce an avalanche. If you are traveling in the highlighted problematic terrain, you can expect to encounter a reactive avalanche problem. 

Of other note is the geographic location where the avalanche activity is occurring. Have a look at the avalanche activity map, under the observations tab. You will notice that the majority of the avalanche activity has occurred in the "snow belt" located in the northwest mountain forecast area. This "snow belt" is where we see the deepest snow accumulations throughout the winter and where we currently have the deepest snow depths now. Less avalanche activity has occurred outside of this area, at lower elevations, and in the southeast mountain forecast area. That lesser amount of avalanche activity is in part due to the shallower snow depths contributing to the avalanche problem being more isolated. While those shallower snow depths are also making travel difficult, so we don't have any data points from areas like Brush Creek and Cement Creek for example.  

Abgedeckte Regionen