Steamboat & Flat Tops

We saw a few, older slab avalanches today that likely ran during or immediately after the January 5th storm, or possibly prior. These occurred on steep, north facing slopes near-treeline. One appeared to break near the ground, and another stepped-down to near the ground. We also saw a natural loose-dry avalanche that occurred possibly today on a steep south facing chute near-treeline, some loose-dry naturals on north aspects, and triggered multiple loose-dry avalanches while kicking cornice chunks onto steep north facing slopes.

Partly cloudy skies to start the morning which cleared throughout the day. Light southwest winds, no blowing snow, and temperatures in the mid-twenties. No new snow.

Snow surfaces were dry on all aspects this morning but turned moist on steeper solar aspects in the afternoon. The height of snow on south and southwest aspects traveled was 65-85cm while north and east aspects ranged from 100-140cm, with some wind-loaded areas up to 170cm. In the snowpits we dug on north and east aspects below and near-treeline, we found a similar structure: a slab that increased from fist to 1-finger hard from the surface to mid-pack sitting atop a rain crust, or dual rain crusts, ranging from a few millimeters thick and breakable to 1 centimeter thick and very stout, all atop facets that were 1-finger to four-finger hard becoming fist hard just above the ground. We did not find the weak layer buried by the January 1st storm here (reported as surface hoar in the Buffalo Pass area and a thin layer of facets in the Gilpin Creek drainage). The primary concern is the faceted snow just beneath the rain crust, though it would seemingly take a large load to trigger an avalanche here. In two extended column tests on two different north facing slopes, we saw fractures with blows from the shoulder occur in the faceted snow just beneath the rain crusts, but only one propagated across the column. Also, kicking chunks of snow off cornices onto north facing slopes, that entrained a solid quantity of surface snow and ran up to 200 vertical feet, did not cause larger slab avalanches.