Turnagain Pass

Cornice falls will be our primary concern. These behemoths have the potential to break on their own as well as with the added weight of a person/people. They are by far the most dangerous avalanche issue right now as they could fall in bus sized (or bigger) masses and tumble to valley bottoms. Add to that the large amounts of snow that can be entrained, or avalanches triggered, along the way and a quiet day in backcountry can quickly change. We have had a handful of these calve off during the past 2 weeks, with the most recent sometime around Saturday March, 9th – as seen in the photo below.

Predicting cornice failure is very challenging, but intense sun with calm wind increases the likelihood. Giving these guys a wide berth is necessary while traveling on ridgelines as well as underneath them. This includes being mindful of any place you stop – for example, to eat lunch, watch your buddies hill climb or put on your skins.

Loose snow avalanches (a.k.a. sluffs) should be fairly easy to initiate today on slopes 40 degrees and steeper. This was the most common issue yesterday. These will come in the form of:

Dry snow – Fast moving but fairly low volume sluffs can be expected on steep shady aspects. With our cold temperatures, shady slopes are becoming looser by the day as the surface snow is faceting.

Wet/damp snow – Southerly aspects will have a crust this morning that might bake down with today’s sunshine and become soft by the afternoon. Light to moderate winds are on tap however and may limit warming of the surface. If crusts do soften expect slow moving damp/wet sluffs to occur. The steeper and more sustained the slope the higher volume and more concerning the sluff. These easily avoidable avalanches can quickly get out of hand in the right terrain where they can pile heavy snow up in gullies quickly for example.

Additional Concerns:
Wind slabs:  North and easterly winds approaching 20mph are possible in scattered areas today. It will be good to keep an eye out for both any fresh slabs formed by this slight bump in wind or old stubborn wind slabs from last week’s high wind event. Any wind slab issue is likely to be confined to the steep “extreme” terrain.

Surface conditions:
Surface conditions are exceedingly aspect dependent (it is March after all).  The northern half of the compass sports mostly soft settled powder with varying degrees of stiffer wind effected snow just below the surface.  The southern half consists mainly of sun crusts. Surface hoar now covers all of these aspects above treeline and is a potential future problem when buried by the next snowfall.