Environmental and Radar Characteristics of Gargantuan Hail-Producing Storms

Large hail can be extremely destructive to crops, infrastructure, and vehicles, and it can also cause severe injuries or even death to livestock and people caught outside. Individual hailstorms can be responsible for billions of dollars’ worth of insured losses. In this study, we investigate storms producing gargantuan hail (defined here as hail ≥ 6 inches or ≥ 15 cm in maximum dimension) to improve the understanding of how and why extremely large hail is formed. To accomplish this, we investigate the radar and environmental characteristics of extremely large hail events and look for similarities, differences, or any unique features that may be indicative of a gargantuan hail threat. The main goals of this study are to: (i) determine any reliable radar signatures indicative of gargantuan hail, and (ii) determine if any unique environmental characteristics are conducive to gargantuan hail production. Through preliminary analysis of 9 cases, we found that 6 of the storms have expansive bounded weak echo regions (BWERs) at high elevations. Additionally, we have found 4 cases of large three-body scattering signatures at low and high elevations. It is interesting to note that the gargantuan hail typically falls outside the region of the highest radar reflectivity factor at low levels. Also, the supercells associated with these gargantuan hail cases do not always have the classical “hook” shape typical of tornadic storms. Near-storm environments from these cases tend to reveal large storm-relative flow magnitudes at low levels. Further details on the quantitative analysis of storm structures will be discussed at the meeting. It is our hope that this research may be able to improve the forecasting and nowcasting of impactful hail events.