Gunnison

Several parties unintentionally triggered surprisingly wide or dense wind slabs at upper elevations yesterday (Example A, Example B).   Be cautious of recently drifted terrain features where the snow surface looks or feels stiffened by wind.  Stay alert for shallow sluffs in very steep terrain where the snow surface is soft.     Small avalanches can be harmful if they push you into gullies, cliffs, or trees.  

With fantastic mountain weather and a relatively deep and strong snowpack lacking deep instabilities, it's a great weekend for traveling in the mountains.  With incremental bouts of snow and periods of wind transport late this week, the avalanche danger has been toeing the line between LOW and MODERATE, which is a fine line for us to hone in on.  Perhaps a day late, or perhaps we're overcorrecting, but we're lifting the danger to MODERATE to account for heightened concerns for wind slab avalanches at higher elevations.   Here's the scoop.

A period of wind drifting late Thursday formed a round of thin wind slabs over the weak facet layers that have been forming all month.  The uptick in unintentionally triggered wind slabs yesterday suggests that wind drifting was more extensive than we expected.  A couple of the slabs broke wider and stiffer than we've seen all month. One was remotely triggered and accompanied by reports of collapsing.  Check out these observations from Mt. Owen, White Rock  Mountain, and Red Lady Bowl.   Some groups found nice soft powder in the alpine as well, so it is clearly not a widespread problem.  If your travels take you to terrain where snow surface starts getting denser, thicker, or grabbier, you are entering wind slab territory.  Wind slab issues should still be small in size, but unlike all the sluffing we've seen recently, they are stiff and dense enough to break above you and around you.  The problem should slowly improve through the weekend, especially on southerly aspects after today's warmup. Thus, we are trending the danger back down to LOW for Sunday unless evidence suggests otherwise. 

We recently listed dry loose avalanches as a problem.  Small doses of snow and continued surface faceting in sheltered terrain have gradually increased the potential size of sluffs this month.  On shady aspects near and below treeline, sluffs can run further or gather a bit more volume than you might expect because of how weak the upper snowpack is.  This is especially true where the snowpack is shallow, either from previous avalanche activity or in extremely steep or rocky terrain.   All of the sluffs we have observed so far this week have been small in size (D1 or D1.5), but they are getting large enough to ruin your day if you get pushed into a terrain trap.  Sluffs are easier to manage but require your attention, never the less.