Advisory Home
Previous Observation
Next Observation
Southeast Alaska Snow Discussion Group
Sample Advisory
Avalanche Danger Scale
Avalanche Photo Galleries
12-26-04 Mt Troy

This was a quick check of how much new snow fell as it cooled on Christmas Eve, how much wind transport and windslab formation there was yesterday, and how the freezing and faceting processes are progressing to set us up for the next storm cycle.

Only 5 - 8 cm of new snow fell as the thaw ended, but it is enough to cushion the runnels and make a much nicer ride. Some 2 cm of surface hoar also helps smooth the ride on the lower, less wind-affected slopes, where there is little or no new snow.

The loose surface layer has all turned to very sugary facets, and the melt-freeze crust is also very faceted. On the higher, wind-exposed slopes, the new snow has blown entirely away down to the icy crust. It is spatially quite variable, in places almost impenetrable, in other places faceted and breakable. The windslabs observed were all very thin and localized, not a threat until they form trigger points under a slab of new snow.

We did no shear tests, as the snowpack was obviously very strong. We skipped densities today and did a quick pit focusing on snow texture, grain type, and temperature gradients.

The melt freeze crust is already frozen some 25 cm thick. There were some glide avalanches during and after the last thaw. It would be wise to give any active glide crack areas wide berth, though the thick frozen crust should begin to limit their movement now.

We do have a setup for the next storm. Bonding to the slippery, variable faceted melt freeze crust and to the overlying facets and windslab is likely to be weak.
The Eaglecrest crew has been hard at work making lots snow during this cold weather. They have filled in from the bottom of the Ptarmigan lift this far already, and are working their way over to the runout of the Sneaky run. The machines spray a mix of compressed air and fine water droplets in front of the blower. The pressure drop chills the water close enough so it freezes in the air before it slowly settles to the ground. The resulting fine ice pellets make a great base that is extremely durable when compared with natural snow. Snowcover on the Hooter lift is thin, but we were able to pick our way down almost to the flats on skis. If they have a couple more days of good cold snowmaking weather, Eaglecrest will be within one good storm of opening.
It isn't deep powder right now, but it is gorgeous. Get out and enjoy the fine weather, the wet spots are all freezing over and travel is becoming easy again after the thaw.
Here's our 25 cent's worth on where to put a new lift at Eaglecrest. A lift somewhere between the two dashed lines would serve all the East Bowl runs, give them a cleaner, more direct fall line, and end high enough to reach the West Bowl too. It could be reached in early and late season from a cat track off the existing Hooter lift, and would end higher than Ptarmigan does now. Hooter would need a rebuild so it could download people when there is not enough snow on the lower slopes, but this setup would have been open since early to mid-November this year if we had it.
A glide avalanche that released December 23 above the Dan Moller cabin. Glide cracks open when the entire snowpack slides along the ground, and glide is especially pronounced when the ground is wet and the snowpack is relatively strong. Some glide cracks just open and no avalanche results, but other glide plates suddenly detach and run as full depth avalanches. They occur more during rain and thaw, but can let go at any time. It is wise to give them a wide berth.
This glide avalanche released December 24 after the rain, thaw, and snowfall ended on the Mt Juneau - Mt Olds ridge. This is a good example of how glide avalanches can release at times when there is no new load, and many would assume that dropping temperatures would be strengthening the snowpack so they would not let go. Glide avalanches are very unpredictable and glide crack areas are best avoided.