Areal-Temporal Variations of Hail Intensity in Illinois

Abstract

Four forms of hail data in Illinois were analyzed to obtain indirect measures of the areal and seasonal variations in hail intensity. These data were also examined to ascertain which hail characteristics correlated best with crop damage. The frequency of intense hail in the crop season (May?October) was found to increase with time, reaching a maximum in September. Insurance statistics indicated that corn damage from hail was usually greater in July than in the later months because corn was more susceptible to damage in July. Observations from a mesoscale network in central Illinois indicated that hailstone sizes and number (volume of ice) and durations of hailstorms related moderately well with crop-hail damage, but that strong surface winds were more closely related. Significant areal variations of hail intensity were found, with some portions of Illinois experiencing intense hail six times more often than other areas.