Good morning. This is Kevin Wright with the Chugach National Forest Avalanche Information Center on Saturday, March 24th 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).
Fresh snow overnight will create pockets of CONSIDERABLE danger in alpine areas that were exposed to wind. CNFAIC Staff problem areas include – South faces and sheltered pockets containing touchy buried surface hoar. Below treeline will be MODERATE. We’ve got a complicated snowpack right now with many different potential problems.
The biggest red flag this morning is new snow with wind. It’s not a lot of new snow, but probably enough to create pockets of unstable wind slabs. Of course this fell on top of multiple persistent weak layers, complicating our current scenario even more. We’ve had quite a few reports of human triggered avalanches in the last week, on all aspects and elevations. The new snow will add even more stress to the already questionable snowpack. The safest terrain today will be shadier slopes and moderate slope angles.
Concern #1 – Storm snow and fresh wind slab
All the new snow overnight will be prone to avalanching given the right trigger. This will be most likely where it fell on top of problem layers, but fresh wind slab by itself could be touchy today. Wind was blowing consistently during the snowfall, loading the West and Northwest slopes and cross loading South gullies.
Concern #2 – Buried Sun Crust
South faces are a bad choice right now. Multiple buried sun crusts have built a complicated network of slabs and weak layers. New snow last night added anCNFAIC Staff slab… I would plan my day to avoid southerly aspects completely.
Concern #3 – Buried Surface Hoar
Multiple layers of buried surface hoar are widespread and have been implicated in quite a few human triggered avalanches. These weak layers have been found on all aspects and up to high elevations. Check out this observation from 2 days ago illustrating the touchy nature of the surface hoar problem.
Concern #4 – Wet loose and wet slab
This will only be a concern if the clouds depart enough this afternoon for the sun to start shining through. New snow, like what fell last night, is more prone to quick changes from sun exposure. South faces should be avoided late in the day.
5 inches of snow fell overnight in some areas with an East to Southeast wind up to 50mph. Up to 3 more inches are possible today. Temperatures were cold enough for all this new precip to stay snow down to sea level.
The front moving across Southcentral Alaska is still dropping some snow this morning, this will weaken to scattered showers this afternoon.
CNFAIC Weather Page and the NWS forecast
Wendy will issue the next advisory Sunday 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.