Gunnison
AvalancheDylan Craaybeek, Griffin Mueller · Feb 13, 2024 · Gunnison
Weather
Bluebird, sunny day with a cold morning around 16F warming up to 50F at the trailhead by 16:00. Some light westerly winds with no notable snow transport throughout the day.
Snowpack
The average height of snow (HS) ranged from 170-220cm on the northerly slopes of Marcellina Mountain. The basal facet layer is still present but it is gaining strength (1F- hard on the hand hardness scale) and showing obvious signs of rounding and bonding. The only slopes where this layer might concern me are slopes that had avalanched to the ground previously this season. The main persistent weak layer of concern is a layer of buried surface hoar that is about 70-110cm below the snow surface. Snowpack tests indicate this layer is becoming more difficult to impact but it still has the potential to propagate into large and dangerous avalanches. Extended column tests would either have propagating failures after 25 taps or no failures and propagation saw tests would show propagating failures after cutting about 33% of the column. With the persistent weak layer of concern buried this deep and growing more stubborn a lack of shooting cracks and collapses does not necessarily mean the slopes you are traveling on are safe. On south, southwest, and west-facing slopes below 10,500ft. there are numerous melt-freeze crusts buried below the snow surface that are well bonded to the adjacent layers and snowpack tests show no instabilities on these buried crusts. The snow surface on slopes in these areas was very wet down around 3-6cm below the snow surface by the end of the day and will refreeze into a thick MFcr overnight. There is some new surface hoar development on northerly slopes in wind-sheltered areas and near-surface faceting occurring in the top 20cm of the snowpack.
Avalanche
Several old avalanches, some a few days old, some several weeks old.