Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Sunday, February 12th at 7am. This will serve as a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).
There is a CONSIDERABLE avalanche danger today for dangerous wind slab avalanches at, and above, treeline. These are possible to be triggered from below and was the case yesterday in two separate incidents. Human triggered dangerous avalanches are likely. Avoiding wind loaded slopes, including areas under or connected to them, is advised until the pack fully adjusts to the latest storm. Below treeline in areas without wind loaded slopes will have a MODERATE danger.
There were two close calls yesterday with two human triggered avalanches that caught, carried and buried, to varying degrees, four skiers. There was one full burial and three partial burials. All skiers are ok. One was in the Turnagain Pass area with some details HERE and the CNFAIC Staff was in the Summit Lake area. You can read more about the Summit details on our Summit Lake forecast; this forecast will now be on Sunday as well as Saturday so check it out.
Wind slab avalanches.
The very touchy wind slabs formed yesterday, and responsible for the Turnagain close call, are still a primary concern today. These recent slabs have proven they can be triggered remotely, including from below, catching those traveling up hill. Additionally, in the Turnagain area, they are not associated with a persistent weak layer so should begin to stabilize in a couple days – but don’t let these large wind slabs lure you out there yet. The obvious signs of collapsing and cracking may have diminished overnight but the slope could still be ‘hanging in the balance’ and just waiting for a trigger.
Today, we are recommending that folks give the steep wind loaded slopes some time to heal. With the past week of storms rolling through every few days, there is uncertainty as to how all these layers are interacting, especially above treeline where observations continue to be limited.
The snowpack below 2000′, where the new snow was running in sluff easily on the buried rain crusts are beginning to bond. The easy triggered slides that were running fast are now harder to initiate.
The storm that continued through yesterday brought almost anCNFAIC Staff foot of snow to favored locations in the Girdwood valley and only a few inches in the Turnagain Pass area. Rain fell below around 500′. The easterly winds were blowing hard, sustained around 60mph with gusts near 90mph.
Today, the storm has moved out and mostly cloudy skies, a chance for a few inches of snow and decreased winds will remain. Winds are forecast to average 20-30mph with higher gusts along the ridges as well as high winds at the lower elevations along Turnagain Arm. Temperatures should remain in the mid 30’s at sea level and decrease with elevation to the low 20’s on the ridge tops. Tonight anCNFAIC Staff low pressure begins to usher in for continued wet and stormy weather early this week.
CNFAIC Weather Page and the NWS forecast
I will issue the next advisory tomorrow morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.