After a week and a half of sunshine and cold temperatures the clouds rolled in, temperatures rose and the winds picked up. Seattle Ridge recorded easterly winds in the 20s and gusting into the 40s starting at 3pm yesterday and continuing through the night. Although we only received an inch of snow overnight at Turnagain Pass and none in Girdwood there is enough old soft snow to blow around. Look for newly formed wind slabs in leeward terrain. Pay attention to slopes where the snow feels stiff, looks pillowed or sounds hollow and watch for shooting cracks. A small slab in the wrong terrain could have high consequences.
The wind overnight may have also stiffened existing slabs and added a little more stress to a layer of buried surface hoar that exists roughly 1-2′ deep. This layer has been responsible for the scattered avalanche activity over the past week and a half (including a large avalanche that occurred on Saturday on Twin Peaks). Most areas, especially in the heart of Turnagain Pass, harbor very loose snow over the buried surface hoar and only sluffs are being seen (no slab). It is the areas where the top foot or two of snow is stiffer from wind effect/loading that we need to watch out for. Also, areas where the buried surface hoar is simply deeper due to higher snowfall amounts from our last storm on January 26th, such as in the Portage Valley zone. If choosing to push into the steep and committing terrain, watch for:
– Areas winds have affected the snow, stiffer snow over softer snow
– Shooting cracks
– Before committing to steep terrain, identify terrain traps like gullies, cliffs or rocks below to consider the consequences if even a small slab is released
*Deep Persistent Slab: Weak snow can still be found near the ground at the upper most elevations in our forecast area, 3,000′ – 5,000′. Although triggering a Deep Persistent Slab is very unlikely, it is worth keeping in mind that poor structure does exist at the high elevations.
Loose Snow ‘sluffs’: In most places the snow is very loose and ’sluffs’ easily on the steeper slopes. Watch your ‘sluff’ and be aware of the consequences below you.
Cornices: Cornices are unpredictable and can break further back along a ridge than expected. Give these features plenty of space.
View of the Twin Peaks Crown on the approach in to investigate on February 5th.
Closer view of the crown. The apex is the trigger point in a shallow rocky spot. The January 21st surface hoar was found to be the weak layer.
Yesterday started out partly cloudy and became overcast in the afternoon. Easterly winds picked up in the late afternoon blowing consistently into the 20s and gusted as high at 59 mph on Sunburst at 2am. Temperatures rose dramatically in the valley bottoms. Portage went from -19F yesterday at 6am to 32F this morning. Upper elevations stayed in the mid to high 20sF.
Today expect mostly cloudy skies and light snow showers. Temperatures will be in the 30sF at sea level and the 20sF at upper elevations. Winds will be easterly 5-15 mph gusting into the 20s. Overnight the clouds will move out and temperatures will be in the teens to mid 20sF. Winds will shift to the north and be light.
Tomorrow should be mostly sunny by mid day with temperatures in the teens to mid 20s and light winds. Thursday the sun continues and then there is a chance of snow into the weekend.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||28||1||.1||62|
|Summit Lake (1400′)||18||0||0||18|
|Alyeska Mid (1700′)||26||0||0||50|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||25||SE||22||46|
|01/26/20||Turnagain||Observation: Pastoral||Allen Dahl|
|01/26/20||Turnagain||Observation: Tincan trees and north side Tincan Ridge||Joe Kurtak, Anchorage Nordic Ski Patrol|
|01/25/20||Turnagain||Observation: Magnum||Ryan Van Luit Forecaster|
|01/25/20||Turnagain||Observation: Tincan||Eric Roberts/ Kakiko|
|01/25/20||Turnagain||Avalanche: Sunny Side of Seattle||Peter Wadsworth|
|01/23/20||Turnagain||Observation: TIncan||Eric Roberts|
|01/23/20||Turnagain||Observation: Goldpan||Allen Dahl|
|01/22/20||Turnagain||Observation: Sunburst||Adrian Beebee|
|01/22/20||Turnagain||Observation: Sunburst||Ryan Van Luit Forecaster|
|01/22/20||Turnagain||Observation: Seattle Ridge||W Wagner Forecaster|
Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: firstname.lastname@example.org
|Area||Status||Weather & Riding Conditions|
This is 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.