Juneau Area Avalanche Advisory
2006-01-01
Mt. Stewart
by Bill Glude, SAAC Observer
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We did a quick trip part way up Mt. Stewart to Bunny Tow Pass today to check out the new snow that fell overnight. The fog was thick on the upper mountain and time was tight, so we did quick work on the lower slopes.

Snow fell to sea level in much of the area overnight, welcome even though it was less than 5cm of moist to wet snow. We found 5 to 10cm of new moist snow above 700m, fluffy on most slopes and windloaded in a few small areas.

We observed no signs of instability except localized shooting cracks in the drifted areas, and minor SE windloading, also localized. The larger lee slopes had only a little snow and it was not yet windloaded enough to be sensitive.

Our slope and traveling tests found some cracking on fresh drifts and sensitive #2 Slab Test results (most of undermined area, clean). Hand shear tests picked out the same windloaded layers. But the larger slopes were still smooth, light and relaxed, up to at least 40°. The new snow improved the ride and kept skis on top of the breakable rime crust of three days ago, allowing easy turning.

It looks much more like winter now, but the same rocks are still lurking close below the surface and only a few spots have enough base to make continuous turns.

The surface layers are likely to turn into sugary faceted grains with the clear weather tonight, and could be a weak layer setup on the thaw crusts below if we get significant snowfall or windloading on them.

We rated the strength ~, the stress -, the energy -, and the structure +, where + is an indicator of a strong snowpack, - weak, and ~ neutral. Slab thickness is still fairly thin and distribution is very localized.

Field Notes
We did no snow pit studies today. The lower layers of the snowpack are quite solid and the new snow is still thin enough to be quite easy to evaluate using observations and slope and traveling tests.
Photos
Freshly drifted areas showed very sensitive snow that cracked easily when loaded, but they were still localized in small areas in the lee of trees, rocks and small terrain features.
The softer surface layers of snow in moderately windloaded areas tested as #2 on the Slab Test, sensitive. Here, the ski pole shows the undermined area. The break is fairly clean and includes most of the undermined area.
Marc Scholten does a high-visibility hand shear test on a 30 x 30cm test block cut out with a ski pole. The new windloaded snow shears off quite easily on the layers below. This test can be easily done with skis and pack on.
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