As Southcentral Alaska sits under a cold, clear and very windy weather pattern, there are areas that have been partially spared by the brunt of the Northwest winds. The ridges along the East side of the road along Turnagain Pass are one of these areas. Folks have been able to find some soft snow and venture further into the mountains without incident. That said, there are areas that have not escaped the major winds. An example would be the Crow Pass region of the Girdwood Valley and the mountains on the Southern end of the forecast zone toward Silvertip. In the Summit Lake area (Summit Snowpack Summary here) two avalanches were seen yesterday on Summit Peak. The key, of course, is to find these sheltered areas, both for better riding conditions but clearly for decreased avalanche danger.
Wind slab avalanches:
It will be another day to watch for slopes with recent or current wind loading. Ridgetop winds should again be moderate to strong – in the 15-25mph range from the Northwest. However, there is not nearly as much snow to blow into slabs as there was at the beginning of this wind event 4-5 days ago. Most of the loose surface snow has blown away or been blown into hard slabs, crusts and sastrugi at the higher elevations. Things to keep in mind with wind slabs:
Cornbiscuit Ridge on the East Side of Turnagain Pass – one of the ‘less windy’ areas.
It is good to keep in mind that there are areas in the periphery of Turnagain Pass that have a poor snowpack structure. These layers are buried surface hoar 1-3′ deep and facets in the mid and base of the snowpack. The ‘wind event’ has loaded and reactivated some of these older layers. The most recent avalanche activity was seen yesterday in the Summit Lake area. Besides Summit Lake, other areas of concern include the Johnson Pass zone and some areas in the Girdwood Valley. Continual winds with this relentless wind event may be loading these old weak layers to the point of failure.
Recent natural wind slabs in the Summit Lake area, this is just to the South of the forecast zone, seen and documented yesterday. (A bit complicated, but the point is two of the 4 avalanches in the photo occurred yesterday).
Brilliant sunny skies were over the area yesterday with very cold temperatures at all elevations – in the single digits and minus single digits. Daytime warming allowed the mid and lower elevations to warm into the upper teens and have only cooled a few degrees overnight. Ridgetop winds during the past 24-hours have averaged near 10mph with gusts into the 30’s from the Northwest.
As Southcentral Alaska sits in a holding pattern of sorts, we can expect similar sunny skies today with continued Northwest winds. Temperatures should warm again today into the upper teens below 3,000′. Ridgetop winds are expected to remain from the North and West in the 15-25mph range with stronger gusts.
For Sunday, sunny and cold weather remain. The one change could be another pulse of stronger Northerly winds. This blocking pattern of high pressure over Alaska looks to remain for the rest of the week. Keep tabs on what the NWS is finding at the bottom of their Forecast Discussion – Long Term Forecast!
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||10||0||0||63|
|Summit Lake (1400′)||9||0||0||29|
|Alyeska Mid (1700′)||12||0||0||58|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||10||NW||10||34|
|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.