|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.|
A fire hose of moisture is pointing our way bringing warm, wet and windy weather to most of Southcentral Alaska. In the Girdwood Valley, Turnagain Pass and Northern Kenai we are seeing light rain up to 1,500′ currently with wet snow above this. The rain/snow line is expected to rise as high as 4,000′ by tonight… If this happens it will be our highest rain line for the season. Precipitation amounts starting yesterday and ending at 6am this morning vary:
Girdwood Valley: 1.3″ water with around 10″ wet snow above 1,500′
Turnagain Pass: Precip sensors are not reading accurately but the snow depth sensor reports 6″ of wet snow
Summit Lake: ~.3-.5″ water with around 4″ of snow
WET AVALANCHES: (two types)
1st type, small(ish): As the storm warms up, rain will begin to fall on the 5-10+ inches of new snow that sits on a crust. Wet loose avalanches will be likely but smaller because they will only be composed of the new snow. Debris could run quite far however.
2nd type, much larger: If the rain and warm temperatures soften/melt the surface crusts, water will be added to an already moist/wet snowpack at the mid-elevations. In this case we could see large wet loose and possibly wet slab avalanches. These can release deeper in the pack or near the ground creating a much larger and destructive slide.
Image below shows the warm Southerly flow that is pumping into Southcentral, AK.
*One of the big questions is, are we now in a “shed cycle”? This is when the snowpack becomes wet and unsupportable and literally sheds off the mountains. The answer is, maybe. It looks like this storm has potential to wet and warm the pack enough below 2,500′ (maybe even up to 3,000′) that we will start seeing large wet loose and wet slab avalanches. These could be hard to discern with the plethora of glide avalanches out there however. Although at the end of the day, it is a bit of a mess at the mid-elevations at Turnagain Pass…
We could see another spike in glide avalanche activity with this warming event. Glide cracks will likely be hard to see with hampered visibility and another reason to stick to mellow terrain with nothing steep above you.
Check out this short clip of a glide avalanche caught on video in the Seattle Creek drainage on Saturday (Credit Allen Garrett). More on that avalanche report HERE. A big thanks to Allen for sending us his photos and video!
We did not see any new glide activity at the Pass yesterday but there were several noted South of Turnagain Pass as well as in Girdwood Valley.
At elevations lucky enough to see dry(ish) snow throughout the day wind slab avalanches will be likely. How thick these will be will depend on how much snow has fallen, roughly anywhere from 6-18″. The storm will likely keep folks out of these high elevations anyhow, but a wind slab releasing from above may trigger a wet avalanche below.
Yesterday’s weather consisted of sunny skies in the morning that were replaced by thick clouds and precipitation by the afternoon as the leading edge of a storm system moved in. Light rain has been falling to 1,000-1,500′ with wet snow above this. Ridgetop winds were strong overnight with averages in the 20-30’s and gusts to 50mph from the East.
Today, we are expecting this warm southerly flow to continue pushing moisture our way from the Pacific. Temperatures will get warmer by the hour through tomorrow and the rain/snow line could reach the ridgetops by tomorrow night (that’s up to 4,000′). Temperature at 1,000′ should rise to the 40’s today. Between .5 and 1″ of water equivalent is expected with another ~.25-.5″ tonight. Ridgetop winds should remain strong, in the 20-30mph range with stronger gusts from the East.
Tomorrow, Tuesday, the moisture should push off to the East before another Southerly flow points our way possibly on Wednesday or Thursday.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||32||5||??||128|
|Summit Lake (1400′)||33||2||0.3||44|
|Alyeska Mid (1700′)||32||10||1.3||110|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||25||SE||24||51|
|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|