Public Observation

Observation Details

Observations

We toured up Glacier canyon past a frozen Dana Lake and up to the Dana couloir from Tioga Pass under clear skies and breezy conditions today. Currently Highway 120 is open from Lee Vining up to the Yosemite Park entrance providing some access to the higher elevations. Overall, the snowpack is minimal with little to no coverage on the sunny aspects and an average of around 2 feet in the shady northerly aspects below tree line where more protected. The sheltered snow on the northerly aspects is faceting under cold overnight temperatures and relatively shallow depths. Snowpack is minimal with inconsistent coverage in the alpine throughout the area with deeper deposits in leeward north and easterly aspects up high. Small cornices already reside at ridgeline on N-E aspects and gullies have cross-loaded deposits on leeward sidewalls. The glacier was exposed and visible in the Dana cirque and there were ribbons of exposed blue ice in the upper north facing couloir. Snow surface conditions were quite firm and variable and displayed the usual effects of high elevation stripping winds. Our high point today was at 11,700ft where the chute opens into the upper apron of the cirque. Here, we found upwards of 6-9ft of dense consolidated snow on the northerly aspect below the Dana couloir where deposition was the greatest from the October storms and likely sluffing and slides that came down from upper terrain. Temperatures up high today were chilly at 21degF @ 1130am with ridge top winds estimated in the 30-40mph range from the SW.

Winds eased a bit in the afternoon and temperatures were much warmer ~33degF at 10700ft where we dug a snow pit on a NW aspect 21deg slope. Although the snowpack is beginning to facet in the sheltered shady terrain at and below tree line, it is still relatively right side up with fairly hard snow (4F+ to 1F+) with very a firm basal ice layer from the warm wet October storm. A melt freeze crust @21cm below the surface in our pit location showed some fracture potential, with hard results in stability tests (CT21 and ECTN22) which both fractured under the melt-freeze crust with resistant planer results. Will have to track how this shallow snowpack changes especially if we remain under dry conditions and the snow continues to metamorphize. I certainly hope though that the key ingredient (snow) continues to fall and we can build upon our already good early season snowpack that we've been blessed with.

Spectacular day out and great to start getting in the swing of things for the winter ahead.

Signs of Unstable Snow