Vail & Summit County
AvalancheDylan Craaybeek · Jan 10, 2023 · Vail & Summit County
Weather
Intermittent snowfall with max precip rate of S2 and steady Light wind with Moderate gusts from the southwest and Moderate snow transport at ridgeline loading the upper portions of leeward slopes.
Snowpack
The bottom line is there is a well-developed persistent weak layer (PWL) making up the bottom 20-40cm of a 150-200cm snowpack. The average height of snow (HS) was around 180-200cm on northerly and easterly slopes near and above the treeline and 130-180cm on west and northwest-facing slopes at the same elevation. These shallower areas (west and northwest) are the more dangerous slopes where it is easier for a human to affect the deeply buried PWL. A prominent rain crust still exists in the basal facets but is showing signs of decomposing and the 20cm of facets above it are far more concerning. Below the treeline the snowpack is around 1 meter deep and there is not much of a PWL on south and southwest facing slopes below 10,000 feet. High extended column test scores and low propagation saw test scores highlight the Persistent Slab avalanche problem issue: it is hard to trigger an avalanche on most slopes but when you do it will go big, propagate across multiple terrain features, you can trigger avalanches remotely, and they will break larger than you suspect. With incoming snow and increased winds avalanches could break near the surface without stepping down and still be concerning, although an avalanche stepping down into weak layers would be the most worrisome. Above the treeline westerly aspects seemed mostly wind-scoured with continuous snow coverage only in concave terrain features such as couloirs on these aspects.
Avalanche
Observed old avalanches that have already been coded. Surprisingly little natural avalanche activity in the Gore almost isolated to the most wind-loaded terrain features.