The Future of Snowstorms in Central and Eastern North America

Snowstorms produce considerable impacts on society and, through their accumulations, modify energy and hydrologic cycles. Assessing how snowstorms will evolve under future climates is essential for understanding changes in the earth-atmospheric system, environment, and society. We investigate the changing snowstorm landscape in the central and eastern United States and southern Canada by employing a dynamical-downscaling regional climate model approach that compares a late 20^th century period against mid- and late-21^st century epochs for two climate pathways that include moderate and pessimistic warming. By identifying, tracking, and cataloging snowstorms across these periods, we illustrate how the frequency, snow water equivalent, and other features of these events may change. Results suggest changes in snowstorm characteristics are most significant for the pessimistic climate pathway, especially toward the end of the 21^st century. There is considerable overlap in event frequency between the historical period and mid-21^st- century projections but declines of 3-10% are still projected for snowstorm counts, hours, cumulative area, and precipitation output. By the end-of-the-21^st century, snowstorm attributes have percent change losses of 6 to 37% versus the historical period, revealing an expected acceleration in loss from the mid to late century. Spatially, snowstorm reduction is most dramatic along and south of the Arkansas, Tennessee, and Ohio River Valleys as the latitude that separates steady snowstorm counts to the north and reduced snowstorms to the south migrates poleward in the future. Similarly, particularly extreme snowstorms decline to the south, with some regions to the north experiencing increase in counts, which affirms prior research that theorizes that some snowfall will intensify as increasing moisture in a warming climate interacts with environments that have temperatures still supportive of snowfall. Significant reductions in the early and late winter weather season snowstorms are projected across all future epochs, revealing the shrinking character of the season. These results provide a set of perspectives on how a dominant cryospheric input—the snowstorm—will change across central and eastern North America in the future.