Abstract
Climate change is forcing the ski industry to modify snow-making
strategies and facility operations. Over-summer snow storage is an
adaptation successfully employed by high-elevation and/or high-latitude
ski centers in Europe, Canada, and Asia. The process involves
stockpiling winter snow and storing it beneath insulation (e.g., wood
chips) through summer. Current methods are empirically-based with few
studies quantifying snowmelt through summer or comparing insulation
strategies. In this project, we evaluate the feasibility of over-summer
snow storage in Vermont, northeastern North America. Soil temperatures
were recorded since June 2017 with sensors 5, 20, 50 cm and 1 m below
the ground surface. In March 2018, two, 200 m3 snow piles were covered
in plastic and wood chips; we monitored their volume bi-weekly through
the melt season using terrestrial LiDAR. We also measured air to snow
temperature gradients under various insulation materials: rigid foam,
open cell foam, and wet wood chips, all with and without reflective
coverings. Away from snow piles, ground temperatures at 1 m depth were
~7C in spring 2017, rising to 12C in summer, and falling
to just above 0C in winter. As depth decreased, ground temperature
became more responsive to air temperature; ground temperature lagged air
temperature at all depths. Below summer snow piles, soil temperature at
all depths remained near freezing through the summer as cold meltwater
percolated into the ground. Snow was lost from each pile at a similar
rate (~1.3 m3 day-1) from late March to mid-June; melt
then accelerated slightly in response to increased air temperature,
solar radiation, and humidity. Large crevasses formed in both piles
along the edge of the plastic sheeting which exposed snow to direct
sunlight. Temperature was at or above 10C over the snow below both rigid
foam and open-cell foam with a strong diurnal variation, regardless of
the addition of a reflective blanket. Beneath wet wood chips covered
with a reflective blanket, temperature remained close to freezing even
though air temperature was > 30C. There was no diurnal
variation, indicating that wood chips effectively buffered thermal
swings. It appears that a reflective surface over >20cm of
wet wood chips is most effective at minimizing summer snow melt in
humid, northeastern North America.