Steamboat & Flat Tops
AvalancheCody M. Perry ยท Dec 28, 2013
Weather
Calm, enjoyable weather during todays tour. Weather recorded at Hahn's Peak Lake area on the Willow Creek drainage floor and on East aspects between 8500 and 9000ft. Sky's were partly obscured with high altitude clouds. Little to no winds observed early in the day and only slightly increasing later. Observed air temps ranged from -6 to -1c.
Snowpack
Site location: 30 degree east facing slope, 8800ft. Overall snow hight in this site was 70cm. Two layers manifest themselves in the pack. One at 40cm- feels like a well developed crust with a clean and robust surface (the crust itself breaks out in chunks, 2 to 3cm thick). The other deeper crust varies at 20 to 25cm in hight- this crust felt and appeared to be decomposing to the touch, not quite as pronounced as the crust above. Multiple CT results didn't occur where I had guessed. Moderate loading steeps (CT-11 & CT-13) resulted in failures along the lower crust boundary. Pulling the blocks off the column would reveal a thin icy crust (I hesitate calling it ice). An ECT showed propagation across the block, failing again at the lower crust, simply by cutting the extended column (ECTPV)* Structure of the snowpack: Between 70 & 40cm was Fist density trending toward 4F. Very thin surface crust with faceting (more pronounced on solar aspects) and very small (.5-1mm) grains in this well bonded newer snow. At 40cm in height the crust goes right to pencil density (2cm thick) along with grain size taking a jump to 2 & 3mm facets. Below 40cm on down to 20cm in snow hight, density is consistent at 4F to 4F+ (2mm facets) until we hit this 2nd crust. This crust (20cm off the ground) is 1F in density and seems to be comprised of 3mm facets welded along an inconsistent icy like plane. Below this layer is loose, sandy 2 to 3mm grains. these lowest facets are large grains no doubt, but I didn't observe any consistent presence of depth hoar at this site. While higher elevations and northern aspects may have depth hoar it should really underscore how variable our current pack is. Not an hour walk west of this site would reveal at pack nearly twice as deep containing the history and memory of older october snow. No Snowpack temp gradients observed. *did not preform ECT test multiple times
Avalanche
Worth noting that a small isolated avy cycle occurred Xmas eve effecting east facing top loads.