|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.|
Today begins the 4th day of stormy weather across the Eastern Turnagain Arm. During this time, Turnagain Pass has seen around 3′ of new snow above 2,500′, wet snow below and rain at the parking lots. The last pulse of moisture was Friday night, adding 6-8″ of new snow. Moderate Easterly winds yesterday loaded leeward slopes and we had a report of one person caught in an 8″ thick slab in the Tincan area, along the ridgeline (just West of Common Bowl). If anyone has information regarding this please pass it on HERE, much appreciated!
Wind slabs will again be the main concern for the upper elevations today. With 5-7″ of new snow and moderate Easterly winds, fresh slabs should be expected and likely in the 8-12″ range. These could also be thicker if a lingering wind slab from yesterday releases. In general, the new snow this week has been stabilizing relatively quickly, however if you catch a slab while or just after it forms, expect it to be reactive and possibly take you for a ride. Feeling for an “upside-down” nature in the top 1-2′ of the snowpack (stiffer snow over softer snow) will be a good clue for sussing out slabs. This can be done with quick hand pits, poking your pole in the snow and walking off the skin track.
Depending on where the rain/snow line is today will determine where wet avalanches will be expected. There was little natural wet activity yesterday and with temperatures similar, if not a bit cooler, we should see little again today. However, human triggered wet loose avalanches (push-a-lanches) were easy to initiate on steep slopes below 2,000′. Something to keep in mind on exiting through mid-elevation terrain; for example, the lower steep section of Magnum’s West Face.
Small wet loose avalanche triggered in steep mid-elevation terrain (~2,000′).
Cornices have grown significantly over the last week. Steer clear of cornices and always know where the cornice begins and the underlying terrain ends. Pick routes on the way up that minimize time spent beneath these features.
Overcast skies and poor visibility were over most of the region yesterday. Light snowfall added just an inch or so to the 8″ of new snow observed at the upper elevations Saturday morning. Ridgetop winds were in the 15-20mph range from the East and Northeast while temperatures were mild, mid 30’s F at 1,000′ and upper 20’s F around 3,000′.
Today, another round of precip is on tap. The Developmental Eastern Turnagain Arm Forecast is calling for .65″ of water which equates to around 5-7″ of new medium density snow at the upper elevations; we might not see quite this much at Turnagain. The rain/snow line should be ~800-1,000′ with temperatures in the mid 20’s F on the ridgetops. Ridgetop winds are expected to be 20-30 mph with stronger gusts from the East and Northeast.
For the next several days we will continue to be in this unsettled weather pattern. Which in short is a series of small low pressure centers rotating around a broad area of low pressure in the North Pacific. How much precipitation and wind will be associated with each disturbance is hard to predict, but nonetheless, the snowpack is growing above 1,500′! (This pattern can be seen on this cool Navy satellite loop – it shows visible images during the day and infrared during the night.)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||32||1||0.2||60|
|Summit Lake (1400′)||35||trace||0.1||11|
|Alyeska Mid (1700′)||34||0||0.01||32|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||23||n/a||9||37|
|12/02/23||Turnagain||Observation: Seattle Ridge||Schauer / Keeler Forecaster|
|12/02/23||Turnagain||Observation: Tincan South Side||Anonymous|
|12/02/23||Turnagain||Observation: Eddies up track||Luc Mehl|
|12/01/23||Avalanche: Sunburst||John Sykes Forecaster|
|12/01/23||Turnagain||Observation: Eddie’s trees||Anonymous|
|12/01/23||Turnagain||Observation: Turnagain – God’s Country||Graham Predeger Forecaster|
|11/30/23||Turnagain||Avalanche: Tincan Trees||Kakiko Ramos-Leon|
|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|