Turnagain Pass

Although the days have been warm lately, today will be hot! As of 6am this morning air temperature along ridgelines are several degrees warmer than previous mornings and sit in the 30’sF. Direct sunshine and light winds could push afternoon temperatures into the 40’sF and even 50F in the mid and upper elevations. The snowpack has already seen many days of a springtime melt-freeze pattern, yet today our hackles should be up for unusual avalanches in the afternoon and evening. Not only are the mid-elevations expected to see wet avalanches, we could see wet avalanche activity on sunny slopes in the high alpine. Wet loose avalanches will be the most likely, but wet/moist slabs are possible.  

Yesterday we know of two new avalanches. One was a glide/full depth avalanche at 5:30pm on Seattle Ridge’s Repeat Offender slide path. This piled 8-10 feet of debris on to the common motorized up-track. See the photos and video below. The other was a glide on Lipps SW face that reported to have released around 11:30am.

Things we can do for a safe day in the mountains is plan ahead. Know the terrain you are traveling and if it will be affected by the sun. The boot test is a great way to assess how the daytime warming is, or is not, affecting the surface. If your boot easily sinks into mushy wet snow, it’s time to get onto shaded slopes or off the one you are on and well away from any runouts. Wet loose avalanches can start small from a person pushing soft wet snow as they ski or ride. If the terrain is large enough, this small slide can turn into a large and unmanageable avalanche. Wet avalanches can send debris far and to places we may not expect.

CORNICES: Cornices are very large and direct sunshine will destabilize them. A cornice fall has the potential to trigger an avalanche on the slope below and could break farther back than expected. 

Glide/full depth avalanche just above the common motorized up-track on the Repeat Offender slide path. Debris covered the up-track with 8-10′ of debris. 

Looking at avalanche and debris from the up-track.

Cornices are peeling off and a significant danger to people getting pulled off a ridge. Getting washed over by cornice triggered avalanche from below is also a hazard.

Glide cracks are popping and avalanching daily. If any time is good to simply avoid traveling under glide cracks, now is the time. A large crack was reported to have released on Lipps SW face yesterday and the Seattle Ridge full depth avalanche is likely a glide that did not have a crack present before releasing; making our current avalanche situation more unpredictable. Remember, glides can release even if a hard surface crust is present (unlike the wet loose and wet slab avalanche problems). Many cracks are opening up in popular terrain and keep an eye out for them. 

With so many old glide avalanches scarring the mountainsides, how do we know if any are new? This is good information as new glide releases tell us they are ‘active’ and more can be expected.  

South of Turnagain in Summit Lake and areas in the interior Kenai Peninsula have a very poor snow structure with variety of old weak layers in the mid pack (facets and buried surface hoar.) Triggering a persistent slab 2-3’ deep as slopes warm in the afternoon sun is possible at the upper elevations. The avalanche seen on Butch Mtn. in Summit Lake last week is a good reminder that sunny hot days can surprise us! Keep in mind deeper weak layers could be lurking in these areas and sunlit slopes are the most suspect.