New snow (6+ inches at Turnagain and 12+ inches in Girdwood Valley) combined with moderate winds speeds ESE-ENE 15-25 (gusting to 40 mph) in the last 24 hrs have formed fresh, sensitive wind slabs on leeward slopes. Wind slabs may be 1-2′ thick. These slabs will be sitting on a variety of old surfaces and may not bond well. Slick wind crusts and soft facets covered most of the terrain prior to the storm. Places where the new snow landed on the slick crusts will be especially suspect. Look for new cornice formation, pillowed and drifted snow and cracking. Winds speeds have mellowed this morning but are expected to pick back up this afternoon. Watch for wind transporting snow and avoid travel underneath actively loading slopes as naturals will be possible.
Photos: National Avalanche Center
Yesterday afternoon. 1.13.17, Snow starting to drift and crack.
In areas unaffected by wind new snow can still act as a slab especially in Girdwood where more snow fell. In addition temperatures warmed up overnight and the storm snow may be slightly upside down with heavier snow over lighter snow. The question during and right after a storm is “How well is the snow bonding to the old snow surface it landed on?” As noted above with the wind slabs, the storm snow landed on a variety of surfaces including slick wind crusts and may not initally bond well. Stepping off the skin track or jumping off your snowmachine to do quick hand pits will be a great tool for determining new snow depth and bonding. Also be on the lookout for loose snow avalanches in the steep terrain where the storm snow may not stick to old surfaces at all. Avoid terrain traps i.e. places where shallow avalanches could pile up more deeply and look for cracking.
As always practicing safe travel protocol is key:
1) Expose only one person at a time
2) Group up in safe zones
3) Have an escape route planned
4) Pay attention to other groups. This could be a busy holiday weekend!
Glide cracks have been slowing opening this week; though we have not seen/heard of any new cracks releasing. Keep an eye out for cracks, which is difficult with new snow and wind, and limit time underneath them. Main Bowl is one of the spots where glide cracks threaten terrain that is commonly traveled.
Yesterday snow fell throughout the day with intensity picking up late in the afternoon. Winds were easterly 15-20 mph with gusts into the 30s and 40s. Temperatures were mostly in the 20Fs with a band of warm air at road level in Turnagain Pass in the 30Fs. Overall temperatures warmed slightly overnight and winds speeds dropped.
This morning the skies are clearing on Turnagain but snow showers continue in Girdwood. These are forecasted to taper off to partly cloudy skies. Colder air will move in this afternoon with westerly winds to 15-25 mph. Temperatures will drop into the single digits tonight. The next storm system is forecasted to arrive tomorrow with another round of snow into Monday.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||33||7||.6||40|
|Summit Lake (1400′)||21||3||.4||14|
|Alyeska Mid (1700′)||28||13||1.4||35|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||24||SE||15||29|
|04/18/21||Turnagain||Avalanche: Turnagain Pass Road Obs||Andy Moderow|
|04/17/21||Turnagain||Avalanche: Road obs||Johnston-Bloom / Moderow Forecaster|
|04/16/21||Turnagain||Avalanche: Seattle Ridge||Wendy Wagner Forecaster|
|04/16/21||Turnagain||Avalanche: Turnagain Pass, non-motorized side seen from Seattle Ridge||CNFAIC Staff Forecaster|
|04/16/21||Turnagain||Observation: Sunburst||Lance breeding|
|04/15/21||Turnagain||Observation: Tincan||Schauer/ Rothman Forecaster|
|04/13/21||Turnagain||Observation: Turnagain Pass Road Obs||A Schauer Forecaster|
|04/12/21||Turnagain||Observation: Tincan||Johnston-Bloom / Latosuo Forecaster|
|04/10/21||Turnagain||Observation: north sides||lance breeding|
|04/09/21||Turnagain||Observation: Girdwood to Turnagain Road Observations||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.