Front Range
AvalancheJohn Gorman · Apr 28, 2024 · Front Range
Weather
28 degrees at the trailhead to start the day, warmed up to 32 degrees at the trailhead by late afternoon. It was mostly cloudy, with extremely brief periods of sun that drastically warmed the air until clouds covered it again. There was a slight breeze throughout the day with periods of strong gusts, especially during bands of more intense snowfall. Wind came from the West. Snow fell throughout most of the day. Waves of stronger snow came in but it was mostly falling at a rate of S1.
Snowpack
The snowpack at below about 10500ft consisted of new snow only, that had melted in patches by the end of the day. Above 11000ft there was new snow on top of a thin crust with what appeared to be more recent snow beneath it. I believe a crust formed some time late yesterday and new snow fell on top of it overnight. We noticed that snow was collapsing under our skis. It seemed localized only but near 11400ft we heard what we believed to be remote whumpfs corresponding to collapses under us. After the 4th or 5th, we stopped in a meadow (39.72096, -105.88041) to dig a quick pit. It was far from scientific, but here’s what I recorded. The HS was 165cm. 20cm of fist hard new snow on top of 3 different crust layers. The bottom crust, 45cm down, was about an inch thick and sitting on top of 10cm of what I believed to be decomposing rounded grains (I had no loupe to be sure but they were wet and could be pressed into a ball) that were not bonding together or with the snow above/below. This is where the collapses were happening, the crust would crack under the weight of a skier. Below the crust sandwiches was a mid pack of saturated, pencil hard large grains of snow. I did not dig to the ground to confirm the whole snow pack was like this, but it went down at least another 50cm. This layer was supportable to boots. The crust layer collapsed all through the day. However, we only noticed mild reactivity on the new snow + first crust interface on test slopes in wind affected areas, not when collapsing the thicker crust above cohesionless snow. Going NTL/ATL, the new snow became very wind affected and deeper than BTL. It became harder to affect the lower crust through this snow, but it could still happen in spots with less new snow on top. Near a ridgeline at about 12000ft my ski partner took a few steps that produced cracks and moved small slabs of new snow below their skis a few centimeters, but we were not on a slope steep enough slope to produce a slide. After 2pm, snow below 11500ft became wet and gloppy. It would stick to and grab at skis.
Avalanche
On a micro feature at about 11600ft on a S facing slope I intentionally triggered a very small windslab that broke only a few inches deep. It was maybe two ski lengths wide and ran no more than 5ft downslope. Not really sure it’s worth coding due to size.