This deep slab problem has already shown itself to be very active during the storm cycle. Now that the precip and wind has lessened, the likelihood of natural avalanche activity will decrease but human triggered avalanches will remain a serious problem. The longer we wait to jump onto steeper terrain, the less likely we will be to trigger a deep avalanche. As recently as yesterday we saw large avalanches triggered by the Department of Transportation. Since that time another 10 inches of snow has fallen in some areas. Some thoughts on the deep slab problem –
– whumpfing and shooting cracks may not be evident
– standard snowpit tests are not suitable for testing deeply buried weak layers
– a lack of observed avalanche activity is not a reliable indicator of potential hazard.
– Waiting 36-48 hours after significant weather changes will decrease the likelihood of triggering (but not eliminate it)
– In some places we have seen the same slope avalanche twice during the recent storm cycle
– Terrain management is the only reliable prevention tool when snow stability is a problem
Wind slab may be a problem above treeline today. We haven’t been able to see avalanche activity within the new storm layers because we haven’t been able to access higher elevation areas in the past 8 days. Recent wind and forecasted wind today may be loading up lee oriented slopes.
It’s been a wet and wild week, and it isn’t finished yet. The graphs below show Turnagain Pass snow depth and wind from the recent weather events.
Today’s weather looks to be mild by comparison. Snow showers are expected today, with 2-3 inches of accumulation. Rain line will be 500 feet. Southeast wind from 30-40mph during daylight hours. Increased precip and wind is expected again tonight. The overall weather pattern is expected to remain active, although not as intense for the remainder of the week.
John will issue the next advisory on Thursday, December 3rd.
|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.