Are Snow Resources on the Northern Plains and Prairies Dwindling?

Snow across the Northern Great Plains and Canadian Prairies constitutes a very essential natural resource. A study to determine if northern snow resources have changed in magnitude over the last forty years was initiated. Snow-course data measured in non-irrigated agricultural fields, near Swift Current, Saskatchewan, reflect the large year-to-year and within-year variability typical of wind-swept plains. This variability rendered direct measurement and detection of snow-resource change difficult. However, analyses of a combined set of daily climatological data (Nipher-shielded snowfall water-equivalent and depth of snow-on-the-ground) at Swift Current show a significant reduction within the last twenty years in the frequency of the number of days with snowcover depths exceeding 10 cm. This reduction was accompanied by a 3.6% increase in winter rainfall, a 17.2% decrease in snowfall, and a 48% decrease in the theoretical snowpack water equivalent. Average daily maximum temperature increased by almost 2 oC between the same early and recent decades. If the change in temperature increased snowpack losses by -34.4% and the conversion of snowfall to rainfall by 13.6%, then snow resources on the northern plains and prairies have diminished by 48%. Extrapolating these data throughout the region, one may conclude that snowcovers on the northern plains and prairies are indeed dwindling.