Watch for changing conditions. Ridgetop winds have picked up and should be blowing the existing loose surface snow into sensitive wind slabs this morning. These fresh slabs are likely to be shallow, around a foot thick, and easy to recognize if you are looking for them. Watch for areas with wind deposited snow and loading patterns in general. Shooting cracks will be an obvious clue wind slabs are tender. Feel for punchy or upside down snow and keep in mind the consequences of the terrain should even a small slab pull out from underneath you. In areas where winds aren’t an issue loose surface snow could move faster and farther than expected.
Trevor Grams sent in this photo from the Library area further back along Tincan Ridge yesterday. Note the loose surface snow available for transport with today’s winds.
As is often the case, the snowpack in the periphery zones of our advisory area such as, Crow Pass and Summit Lake have a shallower snowpack. In these areas, and even those closer to Turnagain Pass itself, we are tracking buried layers of facets and crusts that sit 1-2′ under the snow surface. These layers are most prevalent in the mid-elevations (2000’ – 2700’) and though snow pit data and a lack of avalanche activity has been pointing to an unlikely chance for an avalanche releasing deeper in the pack, additional snow load in the Summit area could start to tip the balance. Evaluate the snowpack and terrain as you travel and be aware that obvious clues like whumpfing may not be present.
Glide cracks are beginning to open up in many places, including Sunburst’s SW face under the weather station, SW face of Tincan Proper, Gold Pan area (behind Cornbiscuit/Magnum) and the one shown below in the Johnson Pass area. These cracks can release at any moment, as this one did below in Johnson Pass. They are not associated with human triggers and the best way to manage the hazard is to avoid being on or beneath slopes with cracks.
Photos of the Johnson Pass area glide avalanche couresy of Matt McKee.
An unnamed longtime CNFAIC pro observer puts his take on this avalanche problem…
Yesterday: Overcast skies were over region yesterday. Evening snow showers favored the Summit Lake area on the Kenai and further South where 4-6″ fell along the Seward Highway. Turnagain Pass and Girdwood only picked up 1-2″. This storm also favored the Anchorage region and North with 4-6″. Ridgetop winds have remained easterly in the 10-20mph range with gusts in the 30’s. Temperatures warmed dramatically overnight and are sitting in the teens along the ridgetops and 20’s at 1,000′.
Today: Snow showers have picked up this morning in Portage Valley and Girdwood. This quick moving front should give the mountains 2-4″ of snow before moving out by midday. Ridgetop easterly winds have picked up as well and should stay in the 15-25 mile range with gusts in the 40’s. Temperatures continue to rise and are expected to hit the upper 20’s at 3,000′ and mid 30’s at sea level.
Tomorrow: What looks like a stronger front associated with the low-pressure in the Gulf moves in on Sunday. This should give the Turnagain area another chance to build up the snowpack. Warmer temperatures could bring a rain/snow mix to sea level, but so far it looks like it will be all snow at 1,000′. Stay tuned!
*Seattle Ridge anemometer (wind sensor) is rimed over and not reporting.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||20||1||0.1||30|
|Summit Lake (1400′)||18||4||0.5||13|
|Alyeska Mid (1700′)||21||3||0.3||17|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||20||*no data||*no data||*no data|