Today Northwest winds are expected to build this morning, 25-45mph in alpine and gusts in the 60’s mph. By late afternoon gusts could reach 75’s mph. Upper Northwest winds in and around Turnagain Pass can be confusing and can funnel through terrain in a more Southwest direction. Luckily there isn’t much snow available for transport in the upper elevations of Turnagain Pass. The December 30th wind event did a pretty good job of hardening the existing surface. With that said there are still some pockets of soft snow that could be blown around and form small fresh wind slabs today. The places to avoid will be steep exposed terrain where getting knocked off your feet will have high consequences. Also if winds do blow from a more SW direction it may make it easier to trigger and older wind slab 4-10” thick on North and East aspects. Watch for blowing snow along ridgtops and cracking will be an obvious sign these windslab are unstable. It is also possible that a small wind slab could step down into an older deeper layer of the snow pack in certain areas. More details on this in secondary concerns.
Current surface conditions in the alpine are variable with some pockets of soft snow, but there is not a lot available for transport. Photo taken 1/4/17 on a SW aspect of Tincan.
Be skeptical of steep loaded (Northern and Eastern) slopes that haven’t avalanched yet. Likely trigger spots will be in thinner areas of the snowpack near rocks or unsupported slopes that may harbor just the right set-up. A 2-3 foot hard slab is sitting on top of very weak snow (facets and buried surface hoar) in these specific areas that haven’t avalanched. A persistent hard slab avalanche could be triggered near ridge tops or mid slope. Obvious signs like cracking and ‘wumpfing’ are becoming less common in the Turnagain Pass area and may not be an early warning sign. This problem will be stubborn to trigger, but should you find the right spot the consequence could be very dangerous. As you travel today identify Northern and Eastern aspects that haven’t avalanched. Old debris is still very visible and is a good way to identify if a slope has avalanched or not.
In the periphery areas (Girdwood, Johnson/Lynx Creek and Summit Lake) where a thinner snowpack exists several observers have experienced collapsing/wumpfing in recent days. Including a recent snowmachine triggered slab in Lynx Creek and widespread collapsing and shooting cracks on Notch Mountain in Girdwood Valley two days ago. It will be in these areas where a persistent slab may be easier trigger.
Poor structure (hard 2-3′ slab sitting on weak facets) was found yesterday on a loaded North aspect of Tincan and remains a concern on loaded North and East aspects.
Over the last two days 3 glide cracks have avalanched in Turnagain Pass; one on a SE aspect of Lynx Creek, SE aspect of Seattle Creek, and the SW face of Eddies. Glide cracks release without any warning and are not associated with human triggers. It is best to avoid existing cracks by not traveling under or within the runout of these unpredictable hazards. Should one avalanche this is the entire snowpack releasing to the ground.
Yesterday skies were sunny becoming partly cloudy in the afternoon. Winds began to increase from the NW averaging 10-15mph. A large temperature inversion began to narrow; ridgetops temps dropped from the low 30F’s to the low 20F’s. Valley bottom temps increased from 5F to 15F overnight. No precipitation has been recorded in the last week. A dense valley fog has been sitting in and along Turnagain Arm for many days.
Today expect temperatures to slowly drop throughout 10-15F by late afternoon. Moderate Northwest ridge top wind are expected to build by early afternoon becoming strong (25-45mph) with possible gusts in the 60’s mph. By early evening gusts could reach 75mph. This could bring the windchill factor well below zero (F) today.
A high pressure system is positioned over Southcentral and Interior, Alaska that will keep temperatures cool and skies clear over the coming days. Winds are expected to decrease by tomorrow afternoon in the Turnagain Pass area, and temperatures will continue to drop possible reaching single digits (F.) This pattern is expected to continue through the weekend into early next week.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||24||0||0||36|
|Summit Lake (1400′)||17||0||0||11|
|Alyeska Mid (1700′)||19||0||0||23|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||25||WNW||12||42|
|05/06/20||Turnagain||Avalanche: Pastoral Peak, north face||Andy Duenow|
|04/10/20||Turnagain||Avalanche: Wolverine||Mike Records|
|04/10/20||Turnagain||Observation: Eddies lookers right shoulder||Matt Yoder|
|04/09/20||Turnagain||Observation: Bench Peak||Mike Records|
|04/04/20||Turnagain||Observation: Pete’s North||Anonymous|
|03/26/20||Turnagain||Avalanche: Tincan – Proper (SW facing)||CNFAIC Staff|
|03/26/20||Turnagain||Avalanche: Seattle Ridge||W Wagner Forecaster|
|03/25/20||Turnagain||Avalanche: Sunburst Uptrack @ 2000′||J. Boisvert|
|03/24/20||Turnagain||Observation: 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.