Steamboat & Flat Tops
SnowpackDaniel Edmiston · May 1, 2013 · Steamboat & Flat Tops
Weather
Small pockets of snow showers rolled thru during the tour. None were particularly potent. Sky changed form overcast to broken and back to overcast several times.
Snowpack
HST=225cm, HN24 only about 5cm, maybe up to 10cm in a few spots. Precip didn't match up with forecast. Dug 120cm pit @ 10500ft on ENE aspect and found some reactivity on the old dust in that the upper 10-15cms would collapse but wouldn't propagate much beyond the skis or shovel blade. Another troubling layer emerged about 2 ft down in the snowpack. Got some mixed results on a few CTs but they all broke in the same spot with the same quality shear. First CT failed @65cms upon isolation (no loading steps completed) with a sudden collapse. Second CT failed @65cms at 13 loading steps also with a sudden collapse. ECT failed at 25 loading steps with full propagation and also a sudden collapse. The weak layer seemed to be a 5cm thick brittle layer that looked like some rounding facets with some ice bonds. The ice bonds between the larger crystals initially had some resistance but would fail dramatically as shown in the CT and ECT. A propagation saw test along this same weak layer caused the 120cm column to fail to the end after 70cms was cut. I dug a small hole in the pit botom til I hit ground and found below these reactive layers was a pencil hard wind slab for about 60-80cms with some rounding depth hoar below that to the ground. I observed a recent ski cut (within 48hrs) from the summit that appeared to have caused a little surface slab release on initial steep summit pitch, perhaps a total of 10 vertical feet. Other old ski cuts looked to have some wet releases on a shallower N facing pitch. On the return trip I skinned over a N facing wind lip and collapsed a 10cm windslab and dropped into about 40cms of facets. The snow has not formed a stable spring snowpack yet.