As time passes and more information is gathered, we are finding that being able to trigger a slab avalanche breaking 2-3′ deep is becoming less and less likely. Although this is a good trend, we can’t write this avalanche problem off just yet. The mountains have a way of humbling us and therefore, it will be prudent to keep in mind a buried layer of surface hoar may sit 2-3′ below the surface. Higher elevation zones that saw prior wind effect are most concerning for finding one of these isolated pockets.
This can be a spooky situation. We can stick to lower angle slopes or if we’re bent on the steep terrain, consider the consequences if part or all of the slope does release. Is there a terrain trap under us? Watch our partners and expose one person at a time. Again, the one known avalanche in this layer was on Wednesday, Jan. 2nd on Seattle Ridge, which was the day after the end of the New Year’s storms. Otherwise, snowpack tests and pits have shown the layer to be either not present or generally unreactive.
The CNFAIC crew out in the God’s County area on the northern end of Seattle Ridge assessing the spatial variability in the Christmas buried surface hoar. Two pits at 1,500′ showed reactivity and propagation propensity, but many others did not.
South of Turnagain – Lynx Creek/Johnson Pass/Summit Lake zone: A poor snowpack structure exists in these areas. The buried surface hoar mentioned above exists as well as facet/crust combinations in the bottom of the snowpack. The New Year’s storm overloaded a variety of these weak layers as can be seen in photos from the avalanche activity throughout Summit Lake. If you’re headed this way, the pack becomes more complex – evaluate terrain exposure and the snowpack as you travel. Remember ‘whumpfing’ and recent avalanches are obvious clues of instability.
The brown cracks easy to see in the Turnagain area are glide cracks. Take a good look at the photos below. The whole snowpack is slowly sliding down the mountainsides and can release into an avalanche at anytime. This is a completely unpredictable situation and one where a human does not play a role. Glide cracks are releasing now. Please don’t be caught in the wrong place at the wrong time and limit/avoid exposure under any crack you see. The most recent glide avalanche we know of was on the south face of Eddies where the glide debris covered fresh ski tracks.
Cracks we know about are in all the hot spots on Turnagain: Lipps, Tincan, Eddies, Lynx Creek, Johnson Pass, Sunburst, Corn Biscuit, Magnum, Seattle Ridge.
Glide avalanche on south face of Eddies – take a close look as the bed surface (ground) could be mistaken for rocks. The debris in this photo covered recent ski tracks – likely released sometime 1/4 or early on 1/5. Photo: Alan Abel.
Glide cracks and an older portion that released (avalanched) Dec. 27/28 – note the small crack opening up on the upper left of photo. These could avalanche at any moment. Photo: Trip Kinney.
Glide crack under Tincan’s Hippy Bowl. These are now opening up at lower elevations. Photo: Mark Turner.
Yesterday: Mostly clear skies were over the region. Ridgetop winds were light from a generally west direction (5-10mph). Temperatures remain cold and inverted; minus single digits in the parking lots and the low teens F along ridgelines.
Today: Mostly clear skies will be over the area again today. Ridgetop winds are expected to remain light, 5-10mph, from the NW. Temperatures stay cold (-10 to 0F) at the lower elevations and in valley bottoms as an inversion remains. Ridgeline temperatures are only slightly warmer at 5-10F… burrr…
Tomorrow: Sunny skies and cold temps are on tap to remain into the week. There is a chance for some clouds and snow flurries on Tuesday. Ridgetop winds at this point look to remain light from a NW direction.
*Seattle Ridge weather station was heavily rimed and the anemometer (wind sensor) was destroyed. We are currently working to replace it.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||6||0||0||58|
|Summit Lake (1400′)||-6||0||0||19|
|Alyeska Mid (1700′)||7||0||0||46|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||12||*N/A||*N/A||*N/A|