Observation: Turnagain

Location: Petes North

Date:
Observer:
Route & General Observations

Toured up to treelike on Petes north and dug two pits, one on a NW aspect and the other on a SW. We wanted to check out the 3.14 interface and determine if we had a scary snowpack structure in this zone.

Wet loose avalanches on SE aspect of Pyramid.Mostly cloudy conditions in Turnagain Pass with some areas receiving direct sunshine.1-2″ thick melt freeze crust at lower elevations and on solar aspects at upper elevations

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.
Weather

Partly cloudy skies and warm temps throughout the day. The southern end of Turnagain Pass seemed to get less sunshine compared to other parts of the forecast area. Despite that we had a very comfortable day in the mountains with good visibility and hardly any wind.

Snow surface

Even without direct sunlight we observed the snow warming progressively throughout the day, especially below 1500'. The top ~2" of surface snow was melt freeze crust that gradually disappeared on N and NW aspects around 1500' but was evident on SW to E facing aspects up to ridge lines. Small roller balls initiated off our skis during our ski down but no other noteworthy wet loose events were noticed in the area. On our drive back to Girdwood we saw some roller balls on the sunny side of Seattle Ridge then noticed a few larger wet loose avalanches at upper elevations on peaks out of Girdwood and the SE face of Pyramid.

Snowpack

We dug two snow pits to collect snowpack structure information on NW and SW aspects. The storm slab layer was about 3' deep and sat on top of a sun crust on SW aspects and a facet layer on the NW. We conducted stability tests in both pits and did not get any significant results (ECT x), which is not surprising considering that the depth of this weak layer is outside of the effective testable limits of a normal stability test. We did however note improving structure in both pits, with the weak layers showing signs of rounding and increasing hand hardness. While these are encouraging signs that the deep persistent weak layer is slowly gaining strength, we need to remember that this information is just from a few locations and it is possible that the weak layer is more preserved in other parts of the forecast region.