Turnagain Pass

Yesterday winds were moving snow, a few inches of snow fell overnight and more is in the forecast for today. Winds remain strong enough to load slopes. This wind direction is opposite of the wind event on Thursday so leeward slopes will also be opposite. Fresh wind slabs may form throughout the day and be sensitive to triggering. Steep, unsupported, leeward slopes and ridgeline starting zones will be most suspect. There may also be old stubborn wind slabs from previous loading. Be on the lookout for wind transporting snow and pillowed or drifted areas. Avoid places where the snow feels stiffer and more affected by winds and watch for cracking. 

 Wind transport on Seattle Ridge yesterday.

Cracking in wind affected snow on Tincan yesterday.

The storm is forecasted to continue today but there is still some uncertainty about how much snow will fall and which sections of the avalanche advisory area will be favored. So far the winner is Summit Lake with 9″ overnight.  Center Ridge Snotel has only received 2″ so far but expect the southern end of the Turnagain Pass towards Johnson to have higher snowfall amounts already. Turnagain Pass could receive anywhere from 4″ to over a foot today. If the upper amounts are received there is potential for storm slab avalanches in places where the new snow doesn’t bond to old snow surfaces. In addition to paying attention to new snow amounts watch for temperature changes within the storm. Warmer snow falling on colder snow can quickly make reactive slab conditions. New storm snow will also add to the potential for loose snow avalanches on steep slopes. Paying attention to changing conditions will be crucial today as the avalanche hazard could increase even at lower elevations if this storm produces. 

A variety of weak layers exist within the snowpack and vary across our region. Following the most recent snowstorm (1/13-1/16) most of the avalanche activity has been observed in the Girdwood Valley. This makes sense since this storm favored this area and left 2-3’ of snow. A handful of small, but deep (to the ground) avalanches were spotted in the alpine this week on Southern aspects of Penguin Ridge, Raggedtop, and Magpie. Summit Lake also had natural avalanches from the Thursday wind event running on weak faceted snow. As more snow falls today remember triggering even a smaller persistent slab could bury a person or take you for a very unfavorable ride over rocks. Pay attention to areas where you can feel weak (sugary) snow under a stiffer snow. If you see recent avalanche activity, experience shooting cracks, or “whumpfing” these are obvious clues that you should avoid steep slopes.