The snowpack is in a tricky stage right now following a 10-day spring storm cycle that caused widespread avalanche activity throughout our region. On Friday and Saturday there were several human triggered avalanches in the Seattle Creek area that were large enough to kill or cause serious injury. Details about these incidents remain unclear, but it appears that folks got really lucky! Saturday afternoon’s sunny skies and warm temperatures also caused two large natural avalanches on Southerly aspects. One in Portage that ran over 3000’ vertical feet and a second avalanche on Pete’s South that triggered a wet avalanche in the mid elevations.
There are several weak layers within our snowpack, the most noteable a reactive and widespread layer of buried surface hoar. There are also varying amounts of snow sitting on these weak layers throughout our region and slab depths range from 2-6+’ thick with Portage and Placer Valley on the deeper side. To complicate the situation spring time conditions and daily warming in the afternoon will increase the likelihood of triggering. This includes shaded slopes with drier snow. Yesterday’s ridgetop winds (10-20mph) helped keep the surface cooler in the Alpine, but today this may not be the case. As we move away from the storm that created our current snowpack, slabs will become harder to trigger and it may not be the first person on the slope. Ease into terrain and avoid terrain traps. Follow safe travel protocols and pay attention to other parties in the area. Obvious clues like whumpfing, shooting cracks, and recent avalanches may not be present.
Location 1st Bowl – The looker left avalanche was reported as a human triggered avalanche and the lookers right slides may be natural or remotely triggered. Photo credit: Eddy Monteil
Buried surfad hoar found in multiple locations on Sunburst on Saturday and was reactive
Last weeks storm caused widespread wet avalanche activity due to above freezing temperatures and rain below 2700’. Now that the storm has passed and we are in a melt/freeze cycle of sorts – solar heating during the day and overnight cooling are the biggest factors that play into the possibility of wet avalanche activity. Last night temperatures hovered around 31F and cloud cover may have trapped some of the day time heat. This may allow today’s solar heating to melt surface crusts a little quicker than the past few days. Temperatures are forecasted to rise into 40F’s, but may reach the 50F’s near sea level. This means solar heating is certain, either through thin clouds or direct sun light. In the morning with freezing temperatures, the snowpack will be more stable, but as this crust starts to degrade in the afternoon, this is when human triggered wet loose avalanches will become likely on Southerly slopes steeper than 35 degrees. This daily warming will also increase the potential for triggering a deeper slab in drier layers in the alpine, on ALL ASPECTS! Pay attention to changing surface conditions if you start sinking into wet snow on your skis or snowmachine avoid steep slopes.
Roller balls on a South aspect of Tincan and storm triggered slabs in the lower elevations from the end of a 10 day storm cycle.
Strong winds throughout the storm cycle combined with heavy snow have created large cornices overhanging leeward slopes. Daytime warming and solar heating will be adding stress to Cornices. Avoid travel on or underneath these backcountry bombs and remember that they often break further back on a ridge than expected. Triggering a cornice has the potential to initiate a large avalanche on the slope below.
Yesterday was a mix of showery weather and partial clearing. Light rain and snow was experienced intermittently through out the day as well as sun shining through patches of clouds. Ridge top winds were from the East, 10-20mph. Day time highs were in the low to mid 40F’s. Overnight there have been varying amounts of cloud cover and scattered showers, but temperatures have dipped slightly below freezing.
A similar showery regime with a mix of clouds and patches of sun is expected. Day time highs may reach the upper 40F’s to low 50F’s near sea level. Scattered snow/rain showers are possible today with up to an 1 € of snow in the alpine (0.1 € of rain.) Rain/snow line is expected to be around 1600′. Light ridge top winds are expected to diminish to calm conditions. Overnight lows should dip below freezing again tonight.
Tomorrow isolated showers are expected, and skies may start to clear by late Tuesday evening into Wed as high pressure settles over Southcentral, AK. Diurnal daily temps swings could range from 25F to mid 50F’s this week.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||36||rain||0.1||73|
|Summit Lake (1400′)||33||0||0||25|
|Alyeska Mid (1700′)||33||trace||0.07||67|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||26||ESE||11||24|
|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.