Vail & Summit County
SnowpackAndrew McWilliams · Apr 18, 2024 · Vail & Summit County
Weather
Overcast skies and temperatures near and above freezing. Some snow squalls left graupel on the surface, but there was no accumulation of new snow. Light to moderate winds from the southwest.
Snowpack
The northerly slopes I toured on today still had mostly dry and cold snow, but water is starting to move through them. Where I dug on a northeast-facing slope water percolated much deeper than where I dug on a north-facing slope at a lower elevation. On the northeast-facing slope at about 11,900 feet, water percolated down about 70cm in a 220cm deep snowpack and large ice bodies were easy to observe. On the north-facing slope at about 11,400 feet, there were thin ice layers within the top 20cm of the snowpack and this pit was in an unsheltered area. An Extended Column Test (ECT) in the pit on the northeast-facing slope produced no results, but when I pulled on the back of the column with my shovel, it broke at the interface of the lowest ice bodies and drier snow with no signs of water percolation. Moderate winds on the ridge were transporting snow onto the leeward side, but no loading was apparent if it was occurring. I dropped a few small pieces of cornice onto a steep and recently loaded part of the slope with no effect. The most recent snow was dry to moist with a thin, breakable crust on the surface. The two-inch thick crust below the most recent snow prevented boots from penetrating below it. The February 2 weak layer is still present in the snowpack as a softer layer of rounding facets with a big grain size difference between it and the layers above and below. My concern with this layer is if there will be a Wet Slab avalanche cycle when the wetting front reaches it. Hard to say when this will happen, but it is something to look out for on slopes where this weak layer is still present. I observed some recent Wet Loose avalanche activity on sunnier slopes that were small in size and likely ran the previous two days, but there was not a widespread shed cycle. I did not find much snow that was unaffected by the recent warm temperatures and there were rollerballs in a northeast-facing couloir with a southerly-facing vertical cornice feature above 12,000 feet.