Yesterday’s impressive snowfall event not only made the news, but also caused a bit of havoc on the Southern Kenai. Here is a rundown of the snowfall numbers around the region – including many areas outside our forecast zone:
Storm Totals: (estimates based on manual reports and station data)
Crown Point (7 miles South of Moose Pass): 40-52″ !!
Moose Pass: 28-32″
Hatcher Pass: 14-17″
Summit Lake: 12-16″
Girdwood Valley: 6-8″
Turnagain Pass: 6-8″
Another 1-3″ is expected in favored areas today. All this snow is very low density and fallen with relatively little wind. As you can see, our forecast zone (mountains around Girdwood and Turnagain Pass) were the losers in the event and avalanche danger remains at MODERATE for slab avalanches and sluffs. A party skiing the Cornbiscuit area triggered several shallow slab avalanches yesterday as well as high volume sluffs. Check out their report on the link.
If skies clear enough for travel to the upper elevation slopes, keep a lookout for where the winds drifted snow during the storm. Triggering a wind slab on the steeper slopes is possible, these are likely to be on the shallow side, 8-12″ thick, and could break well below the ridgeline as was the case with the folks on Cornbiscuit yesterday. Feel for hollow feeling snow, stiffer snow over softer snow and cracks that shoot out from your snowmachine, skis or board.
There is a significant amount of loose snow from not only yesterday’s storm but the snowfall earlier in the week. Expect sluffs to be triggered on slopes approaching 40 degrees. These are likely to be high volume and run fast and far. Sluff management will be key.
At the lower elevations, below 2,000′, a layer of buried surface hoar exists under the last two snowfall events (12-18″ below the surface). Slab avalanches failing on this layer are possible where the snow on top is stiff enough to form a slab. In most locations, the snow is too loose and therefore triggering a slab in unlikely, but it seems the party on Cornbiscuit may have found one of these lower slopes that did indeed have enough of a slab on this suspected buried surface hoar. The lower terrain in Placer Valley is a prime suspect for this set up.
Photo: Buried Surface Hoar 18″ below the surface – seen as a thin grey line. This was at 1,700′ on the Southern end of Turnagain Pass – Pete’s North (Galoob and Haffener).
At the upper elevations, there are a variety of weak layers in the middle of the pack as well as the base of the pack. These are more pronounced in the Girdwood Valley and the Southern end of the Pass where the snowpack is thinner. Although, we have not seen avalanche activity break in these older weak layers, it is good to keep this in mind if venturing into the less traveled zones.
Yesterday’s snow storm, as mentioned above, brought very different snow amounts to the region. Snowfall tapered off at most locations during the day and skies have mostly cleared overnight. Ridgetop winds associated with the snow were 15-20mph from the East and have backed off to 5-10mph overnight from the East. Temperatures have been in the teens at all elevations during the past 24-hours.
Today, instability snow showers are expected to add 1-3″ in favored areas. This means, opening skies in some areas and cloudy with light snowfall in others. Ridgetop winds should be light from the South and East, 5-10mph and temperatures continue to sit in the 10-15F range at all elevations.
For tomorrow, there is a break between storms as a large low-pressure system heads our way. This storm should reach us sometime late Monday or Tuesday. Stay tuned!
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||13||4||0.3||45|
|Summit Lake (1400′)||11||6||0.4||27|
|Alyeska Mid (1700′)||11||4||0.2||42|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||14||E||7||25|
|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: 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.