Assessing East Coast Blizzards Under Climate Change

The Eastern United States is densely populated and highly developed, making winter storms with strong winds and high snowfall among the costliest storms in the United States. Mean annual snowfall is expected to decline in response to a warming climate, but existing snowfall research has neglected to explore how extreme winter storm events will change. For these reasons it is important to determine how the frequency of blizzard events, combining high winds and heavy snowfall, will change in this region with increased atmospheric CO2. In contrast with previous studies that focused on the analysis of station observation data, the GFDL CM2.5 FLOR climate model was used to simulate 300 years in a 1990 control (the present climate) and under doubleCO2 conditions (a future scenario). After extensive analysis of the statistics of snowfall extremes in the model, a “blizzard” was defined as the occurrence of two-day snowfall and high winds exceeding thresholds based on extreme values from the control simulation. The number of blizzard occurrences was then compared between the control and double-CO2 simulations. Mean snowfall consistently decreased across the entire region, but extreme snowfall showed a much more inconsistent pattern with some areas experience increases in extreme snowfall events. Overall, extreme snowfall decreased less than mean snowfall. There are also significant decreases in the number of blizzards in a double-CO2 environment.