The wind picked up 2 nights ago with ridgetop stations reading sustained northwest wind to the 20s and gusts over 50mph in some places. This was enough to produce specific areas of wind slab that can be triggered by a person. Yesterday we found a small mid slope pocket that collapsed a ~30 foot section with shooting cracks within the 2-5 inch thick stiff wind slab. Other people reported more serious occurances yesterday including one person who took a 250-300 foot ride.
Keep in mind that this problem is confined to the surface, meaning it will not step down into deeper layers given the current stability of the snowpack. However, in terrain with consequences it could be enough to be a hazard if caught off guard.
With increased wind we also get increased stress placed on the cornices as they gain mass. Below is a picture from the Summit Lake region that shows a good example of a large cornice failure. Also note the pocket of wind slab to the right that doesn’t appear to be directly connected to the section of cornice failure.
Cold temperatures and clear skies continue this morning. Wind has been moderate to strong for the past 36 hours from the northwest.
Today is the last day of sun in the short-term forecast. We can expect clouds to build throughout the day. By tonight snow is back in the forecast, with 2-5 inches predicted. The storm track is from the west, which is not the typical direction for Turnagain Arm to receive a lot of precipitation. At this time the weather service is predicting more snow for the Matanuska and Susitna valleys.
For long term stability, we can expect a dramatic decrease in stability with new snow in the forecast. Our current snow surface is mostly near surface facets or sun crust, both of which do not allow for quick bonding of new snow.
Fitz will issue the next advisory tomorrow morning, March 22nd.
|01/31/23||Turnagain||Observation: Johnson Pass area||Megan Guinn / W Wagner Forecaster|
|01/29/23||Turnagain||Observation: Tincan Backdoor||AAS-Level 1 1/27-1/30|
|01/28/23||Turnagain||Observation: Sunburst||Brooke Edwards|
|01/28/23||Turnagain||Avalanche: Seattle Ridge||W Wagner|
|01/28/23||Turnagain||Observation: Tincan Common||Tony Naciuk|
|01/27/23||Turnagain||Observation: Sunburst||John Sykes|
|01/27/23||Turnagain||Avalanche: Lynx Creek||Megan Guinn / W Wagner|
|01/25/23||Turnagain||Observation: Cornbiscuit||John Sykes Forecaster|
|01/22/23||Turnagain||Avalanche: Tincan||Schauer/ Guinn|
|01/21/23||Turnagain||Avalanche: Seattle Ridge||Elias Holt|
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.