Good morning. This is Kevin Wright with the Chugach National Forest Avalanche Information Center on Friday, March 30th 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).
CONSIDERABLE danger can be found late in the day for the wet avalanche problem at lower elevations. Most of the region will have a MODERATE danger for buried surface hoar, buried sun crusts, and a warm and weak surface layer on sunny aspects. I expect avalanches to happen in the backcountry today, but I expect them to remain in the smaller size range. Lots of uncertainty is out there, deserving of scrutiny and conservative decisions.
Small avalanches are being reported daily, with multiple problems on nearly all aspects and elevations. The snowpack right now is as complicated as we’ve seen all season, and because of that a lot of folks are managing their terrain conservatively. The problems are generally confined to the upper 1-2 feet of the snowpack. Steep and complex terrain should make you think twice before dropping in.
Concern #1 – Buried Surface Hoar
On drier Northerly aspects we are still finding multiple layers of reactive surface hoar underneath 1-2 feet of variably stiff slab. Check the photos/observations page to browse through quite a few different pit analyses from the last week. This problem can be found at high and low elevations (we saw it at 4500ft yesterday), and is common on the aspects that don’t have the sun crust problem.
Concern #2 – Buried Sun Crust
Anywhere that has seen much sun in the last week will have melt/freeze crusts from the heat exposure. Besides creating poor riding conditions on the surface, the older buried crusts create associated weaknesses that can cause larger slab avalanches.
Concern #3 – Wet loose and wet slab
Late in the day yesterday we saw multiple examples of wet avalanches, both natural and skier triggered. Consistently high temperatures over the last 48 hours have made this problem worse. Small sun sluffs can break into deeper slab avalanches if they affect buried problems like the sun crusts, but even a sluff by itself can gather significant mass in the wet and heavy snow.
The last major snowfall was on Wednesday night when over a foot fell in the Girdwood valley and up to 5 inches in Turnagain Pass. Since that time temperatures have remained quite warm, with above freezing temperatures to 2000 feet for the last 48 hours. Sun exposure was truly baking the South faces yesterday.
There is expected rain and snow today with little accumulation. Tonight, up to 2 inches of snow is forecasted at higher elevations. Wind should remain light for today, and temperatures will reach into the 40s during daylight hours.
CNFAIC Weather Page and the NWS forecast
I will issue the next advisory Saturday 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.