|Travel Advice||Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.||Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.||Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential.||Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.||Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.|
|Likelihood of Avalanches||Natural and human-triggered avalanches unlikely.||Natural avalanches unlikely; human-triggered avalanches possible.||Natural avalanches possible; human-triggered avalanches likely.||Natural avalanches likely; human-triggered avalanches very likely.||Natural and human-triggered avalanches certain.|
|Avalanche Size and Distribution||Small avalanches in isolated areas or extreme terrain.||Small avalanches in specific areas; or large avalanches in isolated areas.||Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.||Large avalanches in many areas; or very large avalanches in specific areas.||Very large avalanches in many areas.|
We haven’t heard of any new avalanche activity since Sunday, when a substantial natural avalanche cycle occurred in addition to a second-hand report of snowmachine-triggered avalanche activity near Seattle ridge. This most recent cycle has a common theme in the fact that all of these avalanches have been quite large, propagating across entire slopes with faceted snow near the ground proving the common and persistent weak layer. Recent results from the snowpit show these weak layers have been slow to gain strength as Fitz’s video here points out. This is a great example of the persistent slab problem that has dominated our primary concern over much of the last three weeks.
As few people have been venturing into the backcountry since the Jan. 5th storm, our information is limited. What information we do have, points toward a snowpack hanging in the balance with a poor structure, moderate strength and high energy. In a nutshell this means that if a fracture is initiated on or below a slope steep enough to avalanche (> 35 degrees) there is good potential that the crack will propagate far and wide, creating a large and unmanageable avalanche. Likely trigger points include thin spots in the slab or near rocks and trees mid-slope.
Maintain astute situational awareness and be mindful of any obvious signs of instability if you travel into the backcountry today. Conservative terrain selection and proper travel protocol will be key.
In areas below treeline where the surface snow is still wet, exists a very poor snowpack structure with free water percolating throughout. Once overnight temperatures maintain below the freezing mark, this lower elevation snowpack will ‘lock-up’ and we’ll likely see Low danger in this elevation band.
Southeast flow continued yesterday ushering in warm temperatures and intermittent bands of rain through the eastern Turnagain arm region with no measurable snow accumulation to speak of. Winds have been light to moderate predominantly from the East and temperatures remained in the 20’s at ridgetop locations and mid-30’s at 1000 feet.
Today looks to be the start of a gradual cool down with temperatures moderating back to near normal values by the weekend. Cloudy skies and 28-33 degrees should usher in 2-3 € of snow above 1000 feet today with slightly warmer temperatures and a rain/ snow mix at sea level. Winds will be out of the East at 15-25 mph and look to decrease to single digits from the North by tonight.
|11/27/23||Turnagain||Avalanche: Tincan Ridge||Schauer/ Stiassny Forecaster|
|11/26/23||Turnagain||Observation: Road report: Slide with dirt on Repeat offender||Anonymous|
|11/26/23||Turnagain||Observation: Pete’s North||Ben Sullender|
|11/25/23||Turnagain||Observation: Tincan trees||John Sykes Forecaster|
|11/21/23||Observation: Spokane Creek||John Sykes Forecaster|
|11/19/23||Turnagain||Observation: Magnum – PMS Bowl||Schauer/ Cullen/ Jonas Forecaster|
|11/19/23||Other Regions||Observation: Sunnyside/Penguin||Jose Ramos-Leon|
|11/19/23||Turnagain||Observation: Eddies||Andy Moderow|