Good morning. This is Chris Engelhardt with the Chugach National Forest Avalanche Information Center on Sunday, April 8th 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).
There continues to be a MODERATE danger today for two specific issues found in the forecast zone’s snowpack. The primary concern still resides in the form of slab avalanches that are failing on buried surface hoar above tree line on northerly aspects. The second concern pertains to wet avalanches at most lower elevations, primarily below 1000′. In these lower elevations, there has been rain and warm temperatures keeping the snowpack from refreezing overnight. Be especially aware of saturated soggy snow in the lower areas such as the Placer Valley and 20-mile. LOW avalanche danger exists for the low to mid elevations that have slopes with supportable crusts.
Yesterday was pretty moist with lots of cloud cover and snow showers throughout most of the day. A modest amount of sticky new snow fell on the forecast area. Snow fall averaged around 2” yesterday, and combined with the previous days dribbling, 6-8” total probably fell during this unsettled period. This new snow has pretty well bonded to the old snow surface due to its wet and warm nature. The biggest issue still exists with shallow soft slabs being triggered on north aspects up high. Layers of buried surface hoar still exist and although proving to be harder to find and trigger, they remain reactive and dangerous if triggered in steep and complicated terrain. These persistent slabs can take you for an unpleasant or serious ride. One person did find one of these slabs on Sunburst Friday.
Primary Concern- Persistent Slab and Wind Slab
Continue to be vigilantly on the lookout for persistent slabs resting on buried surface hoar. This danger is found exactly where most of us want to try to ski to find drier and windblown powder (higher elevation, North facing aspects). Many of these slopes still harbor this lurking dragon. In lower commitment terrain this hazard still remains manageable, but in committing or complicated steep terrain, it may be enough to put you in serious jeopardy if the slab is triggered and you’re swept down. The surface hoar varies in depth from 6” to 1 foot and even deeper in some spots and is still being found to be reactive as recent as this past Friday.
Secondary Concern – Wet Avalanches/Glide Avalanches and Cornices
With today expected warmer temperatures and clearing skies, be especially cognizant of sunny aspects. We saw a fresh glide avalanche yesterday on an east aspect on Seattle ridge. It was in close vicinity of the major up track for gaining Seattle ridge. Check for wet, unsupportable snow and think twice before hanging out under warming aspects, teetering cornices or riding at lower elevations where conditions are becoming increasingly saturated. Small terrain traps in these conditions can become even more hazardous.
Yesterday was primarily cloudy to partly broken skies with numerous snow showers that dusted Turnagain Pass, Summit lake and the Girdwood Valley with 2-3 inches of new snow overall. At higher elevations there was probably more accumulation in the 6-8” realm starting on Friday and continuing through Saturday night. Temperatures remained warm, hovering around freezing during the day at tree line and averaged around 24-27F on ridge tops. Winds were light in the 6-8mph range during the day gusting to over 20 from the east.
Today expects to be mostly clear with mostly sunny skies. Temperatures are supposed to climb to near around 40F at 1000ft and average around low 20’sF at ridge tops. Winds are expected to remain very calm and not much snow is expected.
CNFAIC Weather Page and the NWS forecast
Graham will issue the next advisory Monday 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.