Information from the field yesterday validates the fact that a poor structure (slab/ weak layer/ bed surface) is persisting and a fracture, if initiated has the potential to propagate across a slope. The most reactive snow, and where you are more likely to trigger an avalanche appears to be in the mid-elevation band between 2400’ and 2900’. This is where my partners and I experienced large and frequent collapsing yesterday; prompting us to change our travel plans and seek out mellower terrain. Obvious red flags such as whumphing, recent avalanches and shooting cracks should not be taken lightly as this persistent weak layer is keeping us on the higher end of moderate danger right now.
Above 3,000’ our layer of concern is comprised of smaller, less advanced buried facets still overlain by a slab. This is more difficult to see in a snowpit and whumphing and shooting cracks may not be so obvious until a slope avalanches, making safe travel protocol of the utmost importance. Identify features of concern such as unsupported convexities and mid-slope roll overs. Avoid these areas today or at the least expose only one person at a time and have a well thought out escape route and safe zone if a slope does slide.
A further concern on south facing slopes today has to do with direct sun and inverted (warmer at ridgetops) temperatures. Rapid warming today could be enough to initiate an avalanche on steep, southerly terrain particularly near rock out crops or shallow spots in the slab as seen below.
Natural avalanche observed yesterday on the periphery of the advisory area near Grandview. SSW aspect at about 4,000′.
Calm winds and clear skies prevailed in the backcountry yesterday with temperatures increasing to the low 30’s at ridgetops by days end as high cirrus clouds moved in. Winds are back online (light out of the west) at the Sunburst weather station after a successful anemometer replacement mission yesterday!
Temperatures are slightly inverted this morning with ridgetops readings in the low to mid-30’s while Center ridge (1880′) is reading 24 degrees at 6am. Expect this air to mix and the inversion to lessen as the sun begins heating up the earth’s surface. Winds are expected to be in the 8-20mph range shifting to the southeast as clouds stream into our region this afternoon and evening.
We may see a trace of snow overnight and up to a couple inches by tomorrow night but the upslope nature of this weak surface low looks to favor Anchorage more than the eastern Turnagain arm.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||25||0||0||40|
|Summit Lake (1400′)||20||0||0||6|
|Alyeska Mid (1700′)||24||0||0||23|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||26||N/A||3||12|
*Sunburst wind info is an average from 2pm to 6am.
|04/19/21||Turnagain||Avalanche: Triangle, Seattle creek||Will Morrison|
|04/18/21||Turnagain||Avalanche: Turnagain Pass Road Obs||Andy Moderow|
|04/18/21||Turnagain||Observation: Seattle Ridge, approximately 300 yards south of the up track||Brent Byrne|
|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|
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.