Slabs between 2-3’ thick were deposited over the last week. The bulk of that slab development happened 5 days ago. Those slabs built on top of a wide variety of surfaces. Our field day yesterday showed generally good bonding between these slabs and the underlying surfaces. However, there is a high degree of variability in the makeup of these interfaces. Many areas lack a persistent weak layer between the St Patty’s day slab and bed surfaces, but some areas have a thin layer of weak faceted snow. It is in these areas harboring a thin layer of facets where you will be most likely to trigger a slab avalanche 2-3’ deep. Last week we found this weak layer more widespread in the mid elevations and in sheltered areas in the Alpine.
Sounds tricky? That’s because It is. When the variability of the slab/weak layer interface is this high, it is challenging to accurately assess the stability of the snow below your feet. Tracks on a slope are not a reliable indicator of stability when we have this set up. The best ways to manage this problem are to dig in the snow and pick terrain that allows a margin of error should your assessment be off. Avoiding steep sustained slopes that do not offer escape options will be important today.
Photo of a persistent slab that released yesterday in the afternoon on Tincan. Trigger is uncertain, but is likely natural or remotely triggered by the party pictured at the top of the photo.
Another day of mild temperatures and occasionally intense sun will bring with it an increasing chance of triggering wet loose avalanches as the day progresses. Expect wet loose avalanches to release naturally and be generally low in volume. Human triggered wet loose avalanches could be larger. For that reason it will be important to get off of steep sunlit terrain as the surface snow becomes damp. The possibility also exists for the persistent slab problem (see above) to come in the form of a wet slab on steep sunlit terrain in isolated pockets, as pictured below.
Cornices have grown significantly this week. As always it is important to steer away from cornices and know where the cornice begins and the terrain below you ends. With the onset of Spring also comes long days with potentially intense sunshine. Spikes in temperature as a result of sun and warm air can help to destabilize these behemoths.
Over the past 24 hours temperatures have been mild. Winds have been generally light out of the East and no new precipitation fell. Clear skies allowed the sun to impact solar aspects during the day and the surface snow to re freeze overnight.
Today expect mostly clear and mild conditions with high clouds streaming in from the East later in the day. Winds will be light out of the Southeast at 5mph. Temperatures at 1,000′ will reach into the mid to high 30s F.
We look to be in a generally mild and dry pattern through the weekend as weak Low pressure in the Gulf is held at bay by high pressure building over mainland Alaska.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||36||0||0||56|
|Summit Lake (1400′)||31||0||0||12|
|Alyeska Mid (1700′)||35||0||0||35|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||30||n/a||6||16|
|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: email@example.com
|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.