Good morning. This is Graham Predeger with the Chugach National Forest Avalanche Information Center on Tuesday, April 10th 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).
Avalanche danger today remains MODERATE on north facing slopes above tree line where buried surface hoar is still found. The danger will start out LOW this morning on all CNFAIC Staff slopes and rise to MODERATE as stout crusts break down in the afternoon with increasing solar input.
The snowpack experienced anCNFAIC Staff substantial freeze overnight locking most of our slopes in place. The exception to this is on north facing slopes above tree line where buried surface hoar is still found under tender 8-16″ soft slabs. Elsewhere, stout crusts will be found on the surface this morning. Avalanches will be unlikely where crusts are found to support a skier or snowmachiners weight. However, as the day unfolds and the sun makes its way around the compass, these crusts will begin to break down and the avalanche danger will rise to MODERATE.
Primary Concern- Persistent Slabs
Dry snow continues to be found for the powder connoisseur on shaded north slopes above tree line. This is precisely where we have continued to find shallow buried surface hoar that is now persisting over several weeks. Chris found a large natural slab avalanche in the Portage valley yesterday on a northeast face above tree line during his travels. Buried surface hoar was likely involved and serves a good reminder that these more common shallow slabs that we have been seeing can release into deeper layers. Safe travel protocol, good communication and recognizing and avoiding heuristic traps may be the difference between a great day in the mountains and a “close call”.
Secondary Concern – Wet Avalanches/Glide Avalanches and Cornices
Wet avalanches will not be a concern this morning until the sun has had sufficient time to heat the surface. Yesterday this seemed to happen around 4PM. I suspect this may happen earlier today as temperatures were a few degrees warmer last night than previous nights. Once the snow surface becomes rotten and cannot support your weight (without skis), this is your sign that wet avalanches are possible to trigger. Furthermore, glide cracks are becoming wider and releasing more frequently as more free water percolates through our snowpack. It is good practice to avoid exposure to glide cracks and cornices as we approach mid-April.
Blue bird about sums it up for yesterday! Clear skies, little to no wind and temperatures pushing into the 40’s made for a spectacular spring day in the mountains.
We can expect similar conditions today with slightly warmer temperatures and winds increasing into the 8-17mph range from the east.
CNFAIC Weather Page and the NWS forecast
Wendy 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.