With literally no snow available for transport in lower elevation terrain (it’s all locked up as one thick crust below 3,000’) the depth of any fresh wind slab will be directly linked to the amount of snow we receive throughout the day in the lower elevations. Expect bonding to be particularly poor between the surface and any new snow, as it will be falling on a very slick and stout crust or surface hoar that has formed over the last week. If fresh wind slabs build they will be possible to trigger in terrain greater than about 30 degrees today. With winds predominantly from the north and east, south and west aspects will prove most suspect.
Below 1,000’ any new snow today will be falling on either ice or frozen vegetation where we are essentially building our snowpack, literally from the frozen ground up.
In terrain above 3,500’, the last storm cycle laid down mostly snow (as opposed to rain). Terrain above this elevation is harboring old wind slabs up to a foot in depth resting on weak interfaces. Add to that more wind and a fresh shot of snow today and it will be possible to awaken a persistent slab. Again, leeward slopes on the south and west tilt of the compass should be treated as suspicious if you make it into upper elevations today.
Slabs 3-6 feet thick are sitting on weak snow near the ground in the upper elevations. It is less likely to trigger a deep slab today in comparison to a more shallow wind slab or persistent slab. However, the possibility remains for triggering a slab that can pull out snow to the ground. Unlike the persistent or wind slab concern, deep slabs have the potential to move large volumes of snow. Avoiding likely trigger points, especially areas where slabs are thinner, will lower the likelihood of triggering a deep slab avalanche today.
The deep slab problem is not a concern below 3000 feet where the previously water saturated layers have now frozen into a very strong and stable crust layer.
Increasing mid and high level clouds yesterday were indicative of an imminent change in weather for our region. Temperatures were in the mid 20’s with light winds from the north. Some folks may have even seen a snowflake or two falling at sea level yesterday though it did not add up to more than a trace.
Today the National Weather Service has issued a Blizzard Warning until 7PM for Whittier, Girdwood, Seward and Moose Pass. Winds from the north and east are expected to pick up throughout the day blowing 40-60 mph and usher in 5-12 inches of snow. Temperatures look to be in the mid-20’s at 1,000′ and low-teens to single digits at ridgetop locations. Expect blowing snow to reduce visibility and make travel difficult today.
This pulse of moisture looks to be brief with a return to cold and dry conditions by tomorrow and for the weekend.
|04/21/21||Turnagain||Observation: Sunburst||Schauer/ Behney Forecaster|
|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|
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.