Turnagain Pass

Avalanche danger will rise as a superficial melt-freeze crust breaks down with daily warming and radiation from the sun this afternoon. Light rain fell yesterday, and last night was the second night in a row with above freezing temps in the lower elevations.  Large human triggered avalanches and/or natural avalanches have released daily since Monday from Seward all the way to Girdwood. Some of these avalanches have been remotely triggered while others have released after a skier or snowmachiner were well onto a slope. So far we’ve seen one ‘very large’ natural avalanche, where the crown was a mile-wide, on a NE aspect of Skookum Valley near Placer.  Most of these avalanches have occurred below 3000’, releasing on weak faceted snow on a slick crust, 2-4 feet below the surface. Widespread buried surface hoar and facets have been well documented at all elevations and this poor snowpack structure leaves us concerned about the potential of another very large high-consequence avalanche. A lot of uncertainty remains in the Alpine where slab depths are much deeper and triggering an avalanche could be more stubborn. Today as surfaces become moist and crusts start to break down with daily warming, keep your terrain choices mellow. Slope angles steeper than 30 degrees, and smaller unsupported terrain features are all suspect. There is potential to trigger a slab remotely from below a slope or along a ridge. If you’re playing in the flats, be aware of other parties in the area and avoid runout zones. 

Video of this week’s avalanche cycle in the Kenai Mountains.  

A natural avalanche seen on SE aspect of Seattle Ridge yesterday afternoon. 

Large natural avalanche that released on Tuesday afternoon on a NE aspect of Skookum Valley near Placer. 

Wet loose avalanches or roller balls today are indicative of solar radiation and/ or daily warming temperatures affecting change on the snowpack. We have been seeing this throughout the week with unusually warm temperatures. A wet point release could be small to large and has the potential to trigger a much larger, more dangerous slab, particularly on steep southerly aspects. If the sun comes out this afternoon and evening, natural wet loose avalanches are expected. Pay attention to the surface crust as it breaks down and becomes moist. This will be your first clue that the avalanche danger is increasing.

Small wet point release avalanches were seen yesterday below 2000′ on all aspects in very steep terrain where light rain was falling to this elevation. Today expect these to be more prominent on Southerly aspects at all elevations. 

Wind Slabs: In the upper elevations Easterly winds 20-45mph yesterday were loading leeward slopes and adding stress to a very stressed out snowpack. Triggering a newly formed wind slab up to a foot deep is likely on leeward features in the upper elevations where dry-loose snow was available for transport. Sun and warm temperatures could make wind slabs easier to trigger. A fresh wind slab could step down to older snow in the snowpack and create a much deeper and more dangerous avalanche. 

Cornice Fall: Cornices have grown significantly since the March 9^th storm, an event that arrived with strong winds and dumped 3-4’ of new snow. If the sun appears it will be heating up cornices today and could make them more unstable. Give corniced ridges an extra wide berth and minimize time spent below them. A cornice fall could trigger and propagate an avalanche on a slope below.