Effects of shifting snowmelt regimes on the hydrology of non-alpine temperate landscapes

Abstract

Across the globe, increasing winter temperatures resulting from climate change are affecting how and when snow melts. Despite the significance of snowfall to the annual water budget in mid-latitude, non-alpine regions, there has been limited research into shifting snowmelt dynamics in these areas. This study examines snowmelt changes resulting from warmer winters in the Great Lakes region of North America. Using multiple metrics calculated from station temperature data, recent years (2003–2017) were categorized as “warm” or “cool”, then snowmelt and regional hydrologic patterns within those year types were examined. Systematic differences were observed, including warmer years having less and earlier snowmelt than cooler years. Those changes have, in turn, led to both lower and earlier spring peak flows in streams and decreased net groundwater recharge in the northern regions. Additionally, we show that differences between warm and cool year types become more significant along a north–south gradient; differences between warm and cool years are more pronounced in northern regions with regard to streamflow, net recharge, melt amount and timing. These results provide a framework to examine linked changes between snowmelt and hydrology across high-latitude temperate regions of the world.