An Evaluation of Significant Wind-Driven Hail Events across the United States

Several studies have examined near-storm environments (e.g. Rasmussen and Blanchard 1998; Craven and Brooks 2004) and preferred convective morphologies (e.g. Duda and Gallus 2010) associated with significant severe weather events. However, almost no previous research has examined the antecedent conditions required for significant hail and wind to occur in tandem. These significant wind-driven hail events (WDH) are uncommon, but often create dangerous conditions and widespread destruction of property and crops. In extreme cases, damage estimates can exceed $1 billion (NCDC).

This study offers one of the first climatological studies of significant WDH events across the United States. Using a several step method to identify WDH, a total of 115 events were found from 2012-2016. Radar and environmental characteristics were examined for each identified case, and were compared to established climatologies of tornadoes and significant severe weather. Initial results show that isolated and clusters of cells were the predominant storm type. Nearly 95% of cases exhibited supercell characteristics, but typically did not produce tornadoes. Radar characteristics suggest that a deep hail core and the presence of a deep convergence zone also contribute to the generation of wind-driven hail, and idealized radar depictions of these storms are shown. A continuation of this study may prove useful in identifying events in real-time, which could play an important role in severe weather operations at National Weather Service offices.