|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.|
New snow and wind have combined to create very unstable slabs in the 8-12” range. Ridgetop winds have picked up into the 40 mph range out of the East/Southeast overnight and will remain strong through the day. An additional 10-12” of snow and, more importantly, 1” of H20 forecasted for the higher elevations will increase the size of these slabs into the 2 foot range. These slabs will release naturally in some locations and will be very sensitive to human triggers. Rapid loading that occurred overnight and will continue throughout the day is enough of a trigger to initiate avalanches.
This is not a complicated situation. Avoidance of avalanche terrain is the only way to “manage” this problem today.
A layer of weak snow that sits anywhere from 8” to 3 feet below the surface is the most concerning layer today. Avalanches occurring in the upper layers have the potential to step down to this layer. In cases where this happens, the volume will be large and potential for burial, if caught, is high. Avalanches occurring at this layer have a high propagation potential, which means that fractures can and will travel across slopes and over long distances.
Because of this travel in avalanche terrain is not recommended today (have I mentioned that already?). While this problem exists mainly in the Alpine elevations, it will be important to avoid the runout of terrain from above when traveling in the Treeline elevations.
Rain falling on snow as high as 2,000’ will weaken the surface snow. This will result mainly in wet loose avalanches. Volume will be generally low, as the snow in the mid and lower elevations has already been hit with periods of rain over the past few days and has had time to adjust. With that being said, it will be important to avoid steep terrain where the surface snow is wet. If you find yourself sinking through the snow deeper than your boot it is time to move to lower angled terrain. Consequences of wet loose surface snow moving will become high if pushed into or over terrain traps such as cliffs, gullies, glide cracks, or trees.
Yesterday brought a continuation of warm, wet and windy weather to the area. Temperatures were in the mid 20s F along ridgetops. Temps at sea level climbed into the high 30s – low 40s F. A mix of rain and snow have been falling with the Center Ridge SNOTEL site picking up 5 € of snow containing .5 € of H20. The rain/snow line fluctuated and was around the 1,800′ mark for most of the 24 hour period. Winds cranked back up with Sunburst averaging in the 30 mph range with a max gust of 96 mph.
A strong surface low currently parked just south of the Alaska Peninsula is pulling a warm stream of moisture from the South over the area. Today will bring intense periods of precipitation and high winds, with an additional 10-12 € of snow and 1 € of H20 above the rain/snow line. The rain/snow line should be around the 1,600′ mark. Winds will be strong out of the East at 40-50 mph. Temperatures will remain warm with ridgetops approaching 30 degrees F.
Wind and precipitation intensity should begin to taper off by tonight. Temperatures will cool slightly and a chance for showery precip will remain through the middle of the week.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||33||5||.5||39|
|Summit Lake (1400′)||36||rain||.1||9|
|Alyeska Mid (1700′)||33||2/rain||.4||27|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||27||SSE||27||63|
|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|