Detailed Observation

Date2019-03-30
LocationEastern Alaska Range
ObserverRyan Tansey
AvalancheN

General Observations

A friend and I spent three days ski touring on Kalhabuk Mountain in the Brooks Range (Wiseman, AK).  Since there’s no Brooks Range observation page and I’ve received a number of questions about the conditions from EARAC folks, I figured I’d post our report here.  

The skiing was phenomenal: great spring corn on eastern aspects and 6-12 inches of re-crystallized powder on northern aspects.  We dug two pits on an eastern aspect.  An image of the CT and ECT results are below, along with some videos of the tests (4 videos total posted to my youtube page: CT 1, ECT 2, a video of the depth hoar and one of the strength of the cohesive slab).  In short, there is a strong cohesive slab of varying depth (btw 40 and 90) over buried depth hoar.  The weak layers were somewhat reactive so we stayed largely on lower angle slopes.  We skied one northern aspect of about 33-35 degrees, however this was only because we observed a moose walk down it the previous day without triggering anything (another type of natural avy bomb). 

The snow pack was deep for the Brooks Range, and temps ranged from 20F to 50F.  We observed a number of natural slides (both wet and dry slab) on other peaks in the area, mostly on southern and western aspects due to solar load.  We also observed one small natural wet slab avalanche on Kalhabuk.  We also observed some surface hoar on eastern aspects.  Additionally, we skied down a slide path where a large D3/D4 avalanche appeared to have run during a previous storm cycle.  The slide ran approximately 3,000 feet and snapped dozens of mature old growth trees like twigsn (photo below).  We observed flagging 20 feet up on a number of trees where the slide appeared to have jumped a bank. 

Bottom line: the skiing was spectacular and well worth the drive, but proceed with caution and never trust a depth hoar snow pack.  

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