Climate Change across the United States Northern Great Plains Influencing the Snowpack and the Energy Balance

On average, global temperatures have warmed at a greater rate in the past 50 years than in any preceding period. A warmer climate has been shown to yield less snowfall, a shallower snowpack and an earlier onset of snowmelt. Several studies have examined changes to the ratio of snow to rain throughout the United States, and found that there has not been a change in the amount of precipitation but at many locations there has been a decrease in the amount of snowfall. Across the Northern Great Plains of the central United States, snow accumulation is shallow but persistent for most of the winter. Here, 20 meteorological stations are used to examined climate change across this region over the past 60 years. In general, the amounts of precipitation (and snowfall) are not changing, but the number of days with snow has been decreasing, as the annual maximum and minimum temperatures have been warming. However, there is substantial spatial variability in the trends across this region. Since winter precipitation in solid phase will add fresh snow to the pack and increase its albedo, which alters the energy balance at the surface, albedo is modeled for all stations. Two adjacent stations are explored in further detail to highlight opposite trends.