Good morning. This is Graham Predeger with the Chugach National Forest Avalanche Information Center on Tuesday, April 3rd 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).
Skookum drainage is now closed to motorized use for the season. All CNFAIC Staff motorized areas on the Glacier Ranger District, including Placer Valley, 20-Mile and Johnson Pass remain open.
The avalanche danger is MODERATE today on slopes where buried surface hoar lays in tact. This includes north and east facing slopes at and above tree line where shallow slabs are still relatively easy to trigger. The more sun-affected slopes on south and west aspects are also harboring MODERATE avalanche danger today for wet, loose snow slides in the afternoon. Furthermore, this wet and loose activity can be found on all aspects below tree line.
We found more evidence yesterday of shallow soft slabs balanced on top of at least three buried surface hoar layers in the upper 3 feet of our snowpack. Human-triggered avalanches will be possible today on northern aspects where shadows are still harboring dry snow. In steeper, north facing terrain anticipate these shallow slabs and plan your descent accordingly with escape routes and safe pockets in mind.
Any slope with a southerly tilt will be locked up and quite crusty this morning turning to slush as the sun works its way around the compass today. It’ll be prudent to avoid these south aspects in the afternoon as solar radiation is peaking around 2-3 pm, loosening these crusts and underlying layers.
Primary Concern – Persistent Slab Avalanches
This has been the primary avalanche concern for several days in a row now on shaded, northerly slopes. The shallow, buried surface hoar we are dealing with is kind of like your in-laws who came to ski Alaska this spring. Manageable, but becoming increasingly annoying as they have been here since mid-March and have yet to allow you a day of freeskiing. As with your in-laws, pre-planning escape routes and zones of safety will go a long way in the backcountry today. Avoid slopes above terrain traps such as cliffs or rocky sections where a shallow slab may knock you off balance. If you don’t have a good feeling about a slope, there is no shame in taking the conservative route down and skiing anCNFAIC Staff day.
Secondary Concern – Wet Avalanches, Cornices and Glide Cracks
There has been a lot of what we describe as ‘avalanche dribbles’ on all slopes below tree line and southerly slopes at all elevations. This wet, loose activity has been relegated to the surface so far but as more free water percolates through our snowpack we are likely to see a wet avalanche cycle initiate as we transition into spring.
Yesterday in the Turnagain pass region we saw evidence of fresh cornice fall as well as widening glide cracks. Pay attention to what is above you while ascending and avoid these overhead dangers.
It was a rather brilliant day throughout the core advisory area yesterday. Skies were mostly sunny, little to no wind and temperatures reaching the mid-20’s at ridge tops.
Overnight, valley temperatures are dipping below freezing but expect a steep climb toward the 40-degree mark again today as the sun rises and some low lying fog burns off. It looks to be anCNFAIC Staff glorious day of high pressure on tap with temperatures in the 33-39 degree range at 1000 feet. Moderate north to west gusts will be possible ahead of an approaching frontal trough.
CNFAIC Weather Page and the NWS forecast
Kevin will issue the next advisory Wednesday 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.