Investigating the occurrence of blizzard events over the contiguous United States using observations and climate projections

Over previous decades, the United States has been plagued by severe winter storms or blizzards, which caused millions of dollars in damages. However, the historical trend of blizzard events and the possible impacts of future global climate change on blizzard occurrences remain unclear. In this study, we analyzed historical blizzard occurrences using the observed storm event database, which shows that the Northern Plains, such as North Dakota, South Dakota, and Minnesota, had the most blizzard activities over the past 25 years. No significant trend in blizzard occurrence is found in those regions. When considering blizzards as compound events of strong wind and extreme snowfall, we estimated blizzard occurrences based on wind speed and snowfall in climate datasets, including Automated Surface Observing Systems wind speed, national gridded snowfall analysis, ERA5 reanalysis and historical simulations of 19 models in Coupled Model Intercomparison Project phase 6 (CMIP6), which show a good agreement with the observations with respect to the climatology of blizzard occurrence. In the near-term and long-term future under two emission scenarios, CMIP6 projections suggest decreases in both strong wind and extreme snowfall events, eventually leading to a significantly reduced frequency of compound events. Significant decreases in blizzard occurrence are found in the Northern Plains and Upper Midwest, suggesting potentially reducing the risk of winter hazards over those regions in a warming climate.