Well, it sure looks like winter is taking a 3rd stab at coming to Southcentral Alaska this season. After a high and dry couple of weeks (not to mention our thin snowpack that sits roughly ~40% of average) we are now entering into a stormy weather pattern. Due to the meager snow year, we have been plagued with several weak layers in the snowpack. The most concerning one for this storm cycle is the preexisting snow surface. Before snow began to fall yesterday, we had a mix of 1-2″ of faceted snow and surface hoar sitting on a variable 1-4″ crust (for a better look at this check out Fitz’s video from Sunday). This is a classic weak layer and bed surface combo that now has a 2-3′ slab on top.
During our field day yesterday only 6-8″ of snow had fallen yet we were able to find and easily trigger a slab avalanche 10-14″ thick on a wind loaded slope (photo below). This is a look at things to come. With up to 2′ of storm snow currently and more on the way, slab avalanches up to 2-3′ deep, or deeper in wind loaded locations, are likely. Additionally, the weak snow underneath adds to the potential for slabs to propagate around terrain features and possibly break where you may not expect them to.
Photo: Human triggered slab avalanche in the Tincan Trees, ~1,700′ elevation, West facing.
For today, avoiding avalanche terrain is recommended due to the high volume of heavy snow sitting on a weak surface. Again, avalanches have the ability to propagate wider than expected and can be triggered remotely; this includes from below. Even “in the trees” avalanche terrain exists and there are dangerous terrain traps under small steep slopes/cliffs.
Since 7am yesterday, heavy snowfall has deposited 20+ inches in the mountains around the Eastern Turnagain Arm. Winds were strong from the East with this “Chugach Special” and averaged in the 50-70mph range with a max gust at the Sunburst station of 114mph! Snowfall has tapered off overnight along with the Easterly winds, which are now blowing 20-30 with gusts to 50mph. The rain/snow line crept up from sea level to around 1,000′ overnight along with the ridgetop temperatures which have risen from ~20F to the mid 20’sF.
Storm totals (7am yesterday to 6am today – check this out on the Turnagain Pass snow stake loop!):
Turnagain Pass, 1880′ elev – 20″ snow (1.6″ water equivalent)
Girdwood Valley, 1700′ elev – 21″ snow (1.6″ water equivalent)
Summit Lake, 1400′ elev – 8″ snow (.6″ water equivalent)
An additional 7-10″ of snow (~.7″ water) is on tap today as the remnants of the large low pressure system continues to spin South of the Kenai pushing moisture our way. The Easterly winds are also expected to bump back up today into the 50mph range with higher gusts. Temperatures are expected to remain in the mid 20’sF on the ridgelines and the rain/snow line hover near 1,000′.
Looking forward: The weather models are showing a break in storms late tonight through Wednesday before another – and very similar – low pressure tracks through Thursday/Friday. This should bring another decent shot of precip our way.
|05/06/20||Turnagain||Avalanche: Pastoral Peak, north face||Andy Duenow|
|04/10/20||Turnagain||Avalanche: Wolverine||Mike Records|
|04/10/20||Turnagain||Observation: Eddies lookers right shoulder||Matt Yoder|
|04/09/20||Turnagain||Observation: Bench Peak||Mike Records|
|04/04/20||Turnagain||Observation: Pete’s North||Anonymous|
|03/26/20||Turnagain||Avalanche: Tincan – Proper (SW facing)||CNFAIC Staff|
|03/26/20||Turnagain||Avalanche: Seattle Ridge||W Wagner Forecaster|
|03/25/20||Turnagain||Avalanche: Sunburst Uptrack @ 2000′||J. Boisvert|
|03/24/20||Turnagain||Observation: Turnagain – Road Observations||W Wagner Forecaster|
Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: firstname.lastname@example.org
|Area||Status||Weather & Riding Conditions|
This is 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.