Turnagain Pass

Starting January 8th we have seen several upticks in the wind strong enough to transport snow. The light snow that fell during the New Year’s storm and was enjoyed by powder seekers has now been blown around. Stiff wind slabs have formed in the Alpine and in exposed terrain in the Treeline elevation band. Observers from Summit Lake to Crow Pass have found hard wind effected snow along ridgelines and through valleys that channel the wind. Small natural and human triggered wind slabs have been observed and the avalanche that occurred Friday evening on the Crow Pass trail was a large hard slab avalanche involving wind effected snow. The winds have also been shifting directions and loading different aspects. Overnight the winds shifted again from the east to the west and are forecast to be gusty during the day. About an inch of new snow fell yesterday. Today when traveling it will be important to notice where is snow is drifted, watch for cracking and areas that feel hollow due to hard snow over soft snow. Pay attention to whether or not your skis or machine are sinking into the snow or are you staying on top of very hard snow? Wind slabs can be tricky and let you travel out onto them before failing. Even a small wind slab can be dangerous in steep terrain. The wind effected snow is also most likely sitting on top of weak snow that formed during the stretch of cold temperatures. The wind slabs may linger and be more reactive due to this setup and eventually become another part of our persistent slab issue.

Increases in wind speed recorded at the Sunburst weather station over the past week were enough to transport snow.

Evidence of wind loading and wind slabs. Skier triggered wind slabs on Seattle Ridge and an avalanche on Colorado peak that was possibly skier triggered on the 9th or 10th. 

December 22nd we started talking about the buried surface hoar and buried faceted snow so you might be having a little message fatigue. However, these layers now 1-3’+ deep in the snowpack are still a concern… A “persistent” concern. Now there is potentially even more of slab sitting on top  of these weak layers in wind loaded areas. Additionally, this means there is a chance that a shallow wind slab triggered higher in the snowpack might step down to one of these old weak layers. Choose terrain wisely with consequences in mind if a large avalanche were to occur and use safe travel protocol.

Snowpack on Goat Mtn. Note the weak layer of small facets.

Loose snow sluffs:  On slopes out of the wind the surface snow is becoming looser and looser by the day with the cold temperatures. This is more pronounced at lower elevations due to the inversion. Sluffs are getting larger because of this and gaining volume on longer sustained slopes. One observer described almost having a close call with his sluff on Friday. Getting stuffed into the alders is no joke. Expect sluffing in steep terrain with loose snow.

Cornices:  Give cornices plenty of space and limit your exposure when passing beneath them.

Glide avalanches: Glide cracks continue to open but there have been no recent reports of glide avalanches. However, due to their unpredictable potential to release the travel advice remains the same: limit your exposure while traveling underneath glide cracks.