Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Wednesday, April 18th 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).
This advisory will be updated on Saturday morning. Keep checking our photos/observations page for more up to date information.
Alaska DOT crews may be conducting avalanche hazard reduction along the Seward Highway Wednesday-Friday. Visit 511.alaska.gov for updated information on road closures.
Remember to swing by the Turnagain Pass motorized lot on April 22nd between 4 and 7pm for FREE FOOD and FUN at the 2012 Corn Harvest!!
We have a CONSIDERABLE danger today (Wednesday) for wet loose and wet slab avalanches at all aspects and all elevations. With intense sun and light winds, possibly beginning later today and forecast through Friday, the danger may rise to HIGH – this can happen in a matter of hours. The mountains are warming up and the snow is shedding off in a variety of ways. VERY CAUTIONS travel is necessary in the backcounty and AVOIDING ALL AVALANCHE TERRAIN, THIS INCLUDES RUN OUT ZONES, IS ADVISED.
The “shed cycle” is on as the mountain snowpack continues to warm, lose cohesion and, literally, fall down. It’s that time of year where it’s best to just let the pack do its thing for a week or two while it seasons into a summertime snowpack. Avalanche conditions are dangerous and riding conditions are , well, a sloppy mess.
Several wet loose and wet slab avalanches have been seen in the Eastern Turnagain Arm area during the past few days of rain and snow. The smaller slides are failing at and above treeline in the 2-10″ of very wet snow from 4/15 and 4/16 and larger, up to class 3, slides in the older saturated snow below. The west face of Pyramid Pk. has a few brown streaks indicating glide/wet slab activity has increased on west slopes. South and east continue to produce avalanches and north, though more behind the game, is seeing shallow wet sluffs. North aspects, above treeline, also have the old March 27th buried surface hoar that may still be a player. This photo shows two crowns that look to be dry slab avalanches breaking on buried surface hoar and triggered by an overrunning wet sluff.
The photo below is of Seattle Ridge where slides have been occurring and more are possible.
Primary Concern – Wet Avalanches
Rain below 1500′ and wet snow above for the past 3 days has added ~2″ of water (slightly more in the Girdwood Valley) to our already warming pack. With sun in the forecast for Wed-Fri, including light winds and warm ambient temperatures, the pack will continue its demise. We have seen size 2 and 3 wet slides but these could become larger and running further in the next week. Staying away from any type of avalanche terrain is recommended until the pack adjusts, develops drainage channels and becomes a solid summertime pack.
Above treeline – Persistent Slab
There is a layer of buried surface hoar that sits 12-24″ deep on northwest through northeast slopes at and above ~2500ft. This layer still may be reactive and is suspected to be the weakness in 2 natural avalanches on 4/16 on north facing Tincan mid-slope around 2500′.
Rain and snow has been over our area for the past 3 days and put down ~2″ of water equivalent in the Turnagain Pass area. Rain fell below 1500′, around 2″ of extremely wet snow fell around treeline and upwards of 10″ of heavy snow fell above 3000′.
Skies are clearing this morning and partly sunny conditions should prevail for the next few days. Temperatures look to be near 50F below treeline and in the 40’s above. It’s warm! Winds are expected to be light, 5-10mph from the east.
CNFAIC Weather Page and the NWS forecast
We 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.