A bump in wind this morning will be the main player in the avalanche game today. There has been a change in the weather overnight and skies are cloudy with a chance for 1-2″ of snow. The winds have just begun to increase from the East and are expected to reach the 25-30 mph range before decreasing this afternoon. Though this is a relatively small bump in wind with little new snow, we do have ample light snow available for transport – especially in the Turnagain Pass area. This is from Friday’s localized snow storm that deposited up to 18″ on Turnagain Pass.
The real concern, however, is how the wind may form slabs that can overload the weak faceted snow which sits underneath the recent storm snow. Friday’s storm snow has become very loose due to Saturday and Sunday’s clear and cold weather (see a couple more obsevations sent in yesterday HERE and HERE). This has decreased the slab properties that were present on Saturday and subsequently no new avalanche activity was seen on the Pass yesterday. Today’s winds however could change that by forming new wind slabs. Any fresh slabs formed have the potential to be quite sensitive to human triggers as they will be be sitting on weak snow.
For anyone getting out today, keep an eye out for areas where Friday’s snow is cohesive and especially where it is supportable to your weight. Watching for recent wind deposited snow, cracking or collapsing as well as quick hand pits are good ways to assess this.
At the upper most elevations, weak snow exists near the ground under the majority of the snowpack (4-6+’ deep). This is responsible for the deep slab problem. There is a low likelihood of triggering a deep slab in comparison to the shallow persistent slab. However, the possibility lingers for triggering a slab that can pull out snow to the ground. Avoiding likely trigger points, especially areas where slabs are thinner, will lower the likelihood of triggering a deep slab avalanche.
This problem is not a concern below 3000ft where the previously water saturated layers have now frozen into a very strong and stable crust layer.
Clear skies and ample sunshine greeted folks that were out yesterday. Winds were calm and though temperatures were in the 10F range, it felt quite warm. Valley bottoms remained cold and in the single digits.
Overnight, clouds have moved in and a trace of snow has fallen with a possible 1-2 inches expected through the day. Winds have just starting to increase this morning and are forecast to be in the 25-30 mph range with stronger gusts from the East. Temperatures should increase as well to 20F at 1,000′ and the low teens on the ridgetops. This change in weather is due to a low pressure center spinning in the Northern Gulf that is just strong enough to send a bit of moisture our way.
This system should exit this afternoon and a return to dry weather and mostly sunny skies are in store for Tuesday and Wednesday. For later in the week, we might start seeing more of a classic wintertime pattern with a low setting up over the Aleutians – which means possible snow in the forecast.
Believe it or not the sun has been able to create a crust on southerly slopes. This was seen mainly in the mid and lower elevations (2,500′ ish).
|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.