Today marks a significant pattern change in our weather from the cold, dry high pressure of the last several days to another warm, moist air mass spilling into south-central Alaska. The two factors effecting stability the most today will be rapidly rising temperatures and rain; potentially up to 3,000’.
Wet slab avalanches will be possible to trigger as yesterday’s dry surface becomes saturated at elevations below the rain/ snow line. These may be up to 2’ deep and conceivably could step down into buried weak layers that we know exist throughout the Turnagain and Girdwood Valley zones. Below 2,500’ our snowpack is strong and lacks energy. That being said, the surface has already seen rapid warming at this elevation band and as it becomes saturated with rain later in the day, skiers will be able to initiate wet loose ‘push-alanches’ and point releases in steep terrain, though a cohesive slab will be unlikely at this lower elevation band.
Perhaps more concerning for today; temperatures began their climb across the forecast area yesterday with some dramatic upticks in the mercury this morning (9 deg F in 12 hrs @ Center ridge, 18 deg F in 12 hrs @ Grandview and 28 deg F in 12 hrs at Granite!). This is a big red flag as rapid warming such as this leads to a loss of strength within the snowpack. Though not as dramatic yet (7am) at ridgetop locations, if temps continue to increase throughout the day, particularly in the upper elevations, expect avalanche danger to follow suite with wet slabs becoming more likely.
Temperatures, winds and RH are all on the rise today throughout the forecast area.
Today’s new load is unlikely to be enough to tip the balance and initiate a persistent slab. However, the warming trend over the past 24hrs is acting to decrease the strength of buried weak layers. Rapid warming combined with the potential for a skier-triggered wet slab to step down into buried weak layers has us continuing to keep an eye on this avalanche problem.
With very little snow available for transport, wind slabs today will be relegated to the upper elevations and comprised of new snow. These will grow throughout the day above the rain/ snow line and expect them to become increasingly sensitive to human triggers as the storm progresses. As of 6am this morning ridgetop winds are gusting to 60mph in advance of precipitation.
Yesterday was the end of a period of high pressure and temperature inversions. Clear skies, light winds, and temps in the low teens at 1,000′ (mid- 20’s at ridge tops) have dominated the region for several days now. Make way for our latest warm-up €¦.
Today we can expect warm, wet and windy conditions in the eastern Turnagain arm area. As of 6am this morning the temperature at Turnagain pass is 41 degrees with rain just beginning to show up on the radar. At ridgetop locations, temperatures are in the low-30’s now and will likely see mid-30’s by late in the day. Ridgetop winds will be from the east in the 30-60mph range. The rain/ snow line will be hovering around 3,000′ with .6 €“ 1 € of water forecasted by late tonight.
Unfortunately more warm, unsettled air is on tap for south central Alaska this weekend and into the latter half of next week. Now may be a good time to book that last minute trip to Hawaii or Jackson Hole, depending on what you’re in need of more!
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||33||0||0||32|
|Summit Lake (1400′)||24||1||.2||7|
|Alyeska Mid (1700′)||30||.5||.06||25.5|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||31||E||17||49|
|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.