Turnagain Pass

After strong Northerly winds damaged much of the higher elevation slopes during the last two days, there is another round of wind on tap today. However, these winds are from the Southeast and are bringing cloud cover, warmer temperatures and a chance for 2-3+” of snow tonight. Only small wind slabs were noted in the Turnagain Pass zone yesterday from the past two days, however larger natural wind slabs occurred in the Summit Lake area. No human triggered slab avalanches have been reported – only small loose snow sluffs.

Photo: Wind slab avalanche occurring naturally on Wednesday or Thursday in the Summit Lake area (East facing slope on Fresno Ridge).

Due to the shift in wind direction today, fresh wind slabs may form on areas previously scoured; despite the look of the photos below, there is likely enough soft snow available for transport. The terrain forces winds to blow in very different directions on specific ridgelines, so keep in mind differect aspects may have very different wind effect. New slabs today are likely to be under a foot thick and softer compared to the hard older slabs formed Wednesday and Thursday.

If you headed to the backcounty – watch for:

1. Recent, or ongoing, wind loading on slopes (fresh wind slabs)
2. Old stiff snow over softer snow (old wind slabs)
3. Recent avalanches
4. Cracks that shoot out from your snowmachine, skis, board
5. Collapsing, or whumphing sounds

Photo:  Wind effect on Magnum’s West face. You can see scouring out of older tracks along with smooth rounded areas where snow had drifted/loaded.

Photo:  Another wind affected Southwesterly slope in the Placer Valley, just to the North of the Skookum drainage.

Watch your sluff. Sluffs (loose snow avalanches) triggered by snowmachiners/skiers yesterday were relatively small to medium. With another night of cold temperatures loosening the surface snow, they could be large and fast enough to catch you off your guard today. 

Photo:  Repeat Offender slide path on the East face of Seattle Ridge yesterday. You can see where the Wed/Thur winds have washed the old tracks away on the upper left of photo under the new tracks. You can also see small sluffs initiated on the steepest part of the slope in the lower right portion.

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. Triggering even a smaller persistent slab could bury a person or take you for a very unfavorable ride over rocks. If you see recent avalanche activity, experience shooting cracks, or “whumpfing” these are obvious clues that you should avoid steep slopes.