Very strong “outflow” winds impacted the region yesterday. Cold arctic air rushing down from the North battered the mountains. What soft snow did remain after the Dec 30th wind event was likely taken away with this Jan 5th wind event – a bit like salt on the wound! We only know of one small natural wind slab that released on an Easterly aspect in the Summit Lake area yesterday. Otherwise, there was just too little snow available for transport to produce natural wind slab avalanches.
For Today: Watch for new wind slabs from yesterday, overnight and today (winds are forecast to be moderate from the North and West). These slabs are likely to be shallow, very stiff and could surprise you on a steep slope. Watch for these in any location with wind loading, including lower on slopes. These also have the potential to overload buried weak layers and produce a much larger and dangerous avalanche. The Easterly face of Seattle Ridge is an example of where winds have been loading and known buried weak layers exist.
Safe travel protocol is your friend and if you head out today, remember to expose one person at a time, watch your partners, have an escape route planned and group up in safe zones.
Significant wind transport along Wolverine Ridge (seen from Portage). Winds along this ridge were more Southwesterly due to “terrain forced flow” in complex topography.
The Summit Lake and Kenai Mountains got hit as well with these impressive winds. Below are plumes coming off the Southwest shoulder of Silvertip Peak (far left).
Although the snowpack is wind hardened and tired, it does have a poor structure. There are a variety of weak layers in the middle of the pack as well as at the bottom. The slab on these weak layers is quite variable and hard – and though difficult to trigger, the possibility does exist. Steep wind loaded slopes (Northern and Eastern) that haven’t avalanched yet are the most suspect. Likely trigger spots are in thinner areas near rocks. Obvious signs like cracking and ‘wumpfing’ are becoming less common, making it more difficult to assess slope stability. Heavier loads, such as snowmachines or large groups of people can also be a trigger.
In the periphery areas (Girdwood, Johnson/Lynx Creek and Summit Lake) where a thinner snowpack exists, several observers have experienced collapsing/wumpfing in recent days.
Believe it or not, 3 glide avalanches have occurred in the past 5 days in the Turnagain Pass zone. These are SE aspect of Lynx Creek, SE aspect of Seattle Creek, and the SW face of Eddies. Along with recognizing wind affected snow, keep an eye out for glide cracks and limit time under these. They can have a knack for releasing during cold weather.
Extremely strong Northerly winds impacted the Southcentral mountains yesterday. Skies were mostly clear, but winds were averaging as high as 54mph with gusts to 79mph. These winds brought temperatures down to ~10F on the peaks but scoured out the cold air in the valleys where temperatures rose to the upper 20’sF.
Overnight we have seen decreasing winds, but we are still expecting the North flow to be moderate – averages 10-15mph with gusts into the 30-40’s. Temperatures should remain chilly, 10-15F at most elevations and valley bottoms. Skies look to be mostly clear today.
It seems as though the blocking area of high-pressure over mainland Alaska will persist into next week. Along with this will be clear skies, cold temperatures and no expected precipitation.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||19||0||0||35|
|Summit Lake (1400′)||21||0||0||11|
|Alyeska Mid (1700′)||20||0||0||23|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||16||N||38||79|
|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.