Front Range
Snowpackmarkus beck · Jan 7, 2013 · Front Range
Weather
Clear skies with Temps in the low/mid 20F, significant temp difference between sun and shade. Cold nights. Calm except light winds at ridgetops producing minor windloading into N-E aspects.
Snowpack
BELOW TREELINE: Hs is generally in the 1-2ft range and mostly faceted. Depth hoar is growing in grain size and the basal DH layer is getting thicker. Various surface faceting observed including moderate/large size surface hoar. The storm snow has mostly "recycled" into surface/near-surface facets. in the mid pack, the occasional old thin sun crust could be observed but that too is faceting. Overall, the snowpack is very weak but lacks tension due to the lack of a slab (some very isolated areas mark the exception: the most suspect slopes are very steep open glades on N-SE that have a stouter mid pack from previous more significant windloading). AROUND TREELINE: Hs varies dramatically from a few inches to 4ft or so. The snow structure is more layered resting on a basal layer of DH. Old windslab, buried surface facets, and (on sunnier slopes) buried sun crusts make up the snowpack. In shaded areas, the structure is going to mostly facets whereas in sunnier slopes this process is less pronounced though buried facets are present. Though strong-over-weak layering is widespread, the snowpack appears to have little tension. Most suspect areas are 35+dgr on N-SE with a snowpack that is 3ft or deeper that have not avalanched before. ABOVE TREELINE: Hs varies dramatically from a few inches to several feet. Lots of windslab stacked on top of windslab though I did observe some buried surface facets inbetween some of those stacks. The surface is hard to very hard and many of those buried windslab layers are 1F to P. At the base of this structure are widespread DH. Most suspect slopes are35+dgr on N-SE that have not avalanche before. OTHER OBSERVATIONS: We had a couple of decent collapses below treeline on a very low angle ENE aspect; unable to produce any other signs of instability. Most steep slopes 35dgr and steeper have avalanched (most of them "wall to wall", large R sizes) 5 or more days ago. Recent moderate winds and minor snowfalls have only partially refilled the startzones. I dug around at one of those slopes (E, 36dgr, above treeline) and noticed that most of the refill consists of up to 3ft of faceted snow.... while currently and with that structure not of concern, those slopes will have an even greater potential for avalanching once refilled with new slab. SLOPES OF CONCERN currently are those 35+dgr on N-SE above and around treeline. Soft slab is transitioning in most areas into hard slab. These hardslabs are generally supportive of a skier's weight though may be triggered on areas where that hardslab is less thick or softer (small changes of incline and aspect, margins of the slab, near rocks and trees) and likely will result in a larger more powerful avalanche big enough to bury, injure or kill. Where the surface snow remains softer, pay attention to whether these is from recent windload or surface faceting and overlays a stouter mid pack- these small pockets are suspect on 35+dgr and are found most likely in crossloaded couloirs and near ridges above treeline on N-E. Bridging is a two-sided sword to begin with (low likelihood of triggering, high consequences when triggered) but the current snowpack does not provide anything like a "reliable" bridging because its generally not deep/stout enough.