| Recent Avalanches? | Yes |
| Collapsing (Whumphing)? | No |
| Cracking (Shooting cracks)? | Yes |
Observation: Girdwood
Location: Upper Crow Creek
Toured up to crow pass trailhead and up to treeline on the west side of the creek
Obvious signs of instability
Observer Comments
We saw a fresh looking D1.5 to D2 size debris pile at the base of a steep south facing ridgeline at about 3000' and triggered some small shooting cracks in a heavily wind loaded gully feature.
Weather
Clouds were overcast to obscured throughout the day with just a few sucker holes mixed in. Occasional light snow in the afternoon.
Snow surface
Settled powder below treeline with some wind effect above.
Snowpack
We dug pits in a few locations trying to evaluate whether there were any deeper weak layers in this area, which has an overall thinner snowpack compared to locations near Alyeska or Turnagain Pass. Our first pit was at 2500' on an East aspect with 170 cm height of snow. Here are the notable layers:
- 2 layers of decomposing new snow within the upper 15-30 cm of the snowpack
- New Years Crust (NYC) buried 40 cm. The crust was 10-15 cm thick with alternating layers of ice and snow and very strong in the first location
- November facets buried 110 cm with 4F hardness and 1-3 mm rounding facets. The layer was up to 20 cm thick above the firm Halloween crust
We had ECTN results on the 2 layers of decomposing new snow and nothing on the November facets, which I think was due to the strength of the upper snowpack and NYC. We tried a PST on the November facets here but some user error lead to unreliable results.
Our second pit location was just uphill at around 2700' on a S aspect with 160 cm height of snow (see photo for structure). We found a similar very weak structure in the November facets and the layer was only buried 80 cm. Again we had no propagation our ECT, but we got a PST 30/100 end in the upper November facets. Given the recent avalanche in Summit Lake on this old buried weak layer and the large widespread avalanches caused by this layer back in late November into mid December it is worth keeping it on our radar. Especially in areas with a thinner overall snowpack.
Shooting crack on a small cornice over a wind loaded gully near treeline.
The clouds never quite cleared today. We hoped for better visibility in the afternoon but it never came. At least the snow below treeline was relatively preserved from all the recent winds.
Snowpack structure for upper pit