Vail & Summit County
AvalancheDylan Craaybeek · Feb 10, 2023 · Vail & Summit County
Weather
Cold, Clear morning 0F in Carbondale at 7:30 and 10F in Vail at 9:15. Remained Clear and Calm all day with an occasional Light northwest gust and no snow transport on any visible ridgelines. Warmer temperatures throughout the afternoon reaching low 20's F.
Snowpack
The primary weak layer of concern is a thin (1-3cm) layer of 1mm Facets (FC) buried about 60-90cm deep. This weak layer was found on northwest through east to southeast facing slopes above 11,000 feet in elevation and is showing clear signs of rounding and gaining strength from numerous extended column tests only getting propagating results with additional loading steps and propagation saw tests failing after cutting about 50% of the column. There are two other weak layers in the middle of the snowpack similar to the above mentioned persistent weak layer but show no evidence of being problematic and only get non-propagating failures with additional loading steps on ECTs or shovel shear tests. The mid-November persistent weak layer is uniformly buried 180-250cm deep with windward aspects being shallower and leeward, wind-loaded aspects being deeper. A full-profile snowpit on a representative north-facing slope near the treeline showed 18 inches of snow water equivalence (SWE) in 185cm of now making up the snowpack on top of the rounding depth hoar (DHxr). With close to 2 meters of snow and about 18 inches of SWE separating backcountry travelers from the basal facets it seems incredibly unlikely for a human to trigger an avalanche that breaks near the ground unless they travel on very rocky, uneven, wind-scoured, westerly slopes. The surface snow on sunny aspects was quickly warming throughout the day with incoming shortwave radiation causing numerous Wet-Loose avalanches at all elevations and Moist to Wet surface snow on all slopes steeper than 15 degrees facing a southerly direction. A prominent melt-freeze crust (MFcr) developed throughout the day on the current snow surface below 10,000 feet on southerly aspects that was mostly refrozen within an hour of the slope getting shade.
Avalanche
Observed a few avalanches on nearby ridgelines all on wind-loaded terrain features and one looked fairly recent (within 48 hours). One old avalanche near Bald Mountain previously coded in this observation: https://classic.avalanche.state.co.us/caic/obs/obs_report.php?obs_id=74144