@article{b75ac603e5ef44d78b567e59cd86f762,
title = "Sub-Severe and Severe Hail",
abstract = "The occurrence and properties of hail smaller than severe thresholds (diameter < 25 mm) are poorly under-stood. Prior climatological hail studies have predominantly focused on large or severe hail (diameter at least 25 mm or 1 in.). Through use of data from the Meteorological Phenomena Identification Near the Ground project, Storm Data, andthe Community Collaborative Rain, Hail and Snow Network the occurrence and characteristics of both severe and sub-severe hail are explored. Spatial distributions of days with the different classes of hail are developed on an annual and seasonal basis for the period 2013–20. Annually, there are several hail-day maxima that do not follow the maxima of severe hail: the peak is broadly centered over Oklahoma (about 28 days yr-1). A secondary maximum exists over the Colorado Front Range (about 26 days yr-1), a third extends across northern Indiana from the southern tip of Lake Michigan (about 24 days yr-1 with hail), and a fourth area is centered over the corners of southwest North Carolina, northwest South Carolina, and the northeast tip of Georgia. Each of these maxima in hail days are driven by sub-severe hail. While similar patterns of severe hail have been previously documented, this is the first clear documentation of sub-severe hail patterns since the early 1990s. Analysis of the hail size distribution suggests that to capture the overall hail risk, each of the datasets provide a complimentary data source.",
keywords = "Agriculture, Atmosphere, Climatology, Databases, Hail, Insurance, North America, Sampling, Statistical techniques, Thunderstorms",
author = "Elmore, {Kimberly L.} and Allen, {John T.} and Gerard, {Alan E.}",
note = "Funding Information: To offset these limitations remotely sensed climatologies of estimated hail occurrence are now possible (e.g., Cintineo et al. 2012; Murillo et al. 2021; Wendt and Jirak 2021). These technologies are available over a near complete spatiotemporal range for the continent outside of the western CONUS. However, these approaches focus strongly on the maximum expected size of hail, and through lack of appropriate validation data, generally leave sub-severe hail as an afterthought, despite its societal implications. Despite the efforts of projects such as SHAVE (Ortega et al. 2009; Ortega 2018), or those in Switzerland (Barras et al. 2019) a greater volume of sub-severe hail reports is needed to understand the best approach to characterize the total frequency of hail days, the properties of smaller hailstones, and sub-severe hail economic impacts. The question of whether small hail occurrence has changed over time is also a reason to maintain and expand such datasets. For example, over both China and France there have been decreasing trends in smaller hail (Li et al. 2016; Sanchez et al. 2017), contrasting the stationary frequency or increases seen for larger hail in the United States (Allen et al. 2015; Tang et al. 2019). With climate projections indicating strong decreases to smaller hail, approaches are needed to monitor these events (Mahoney et al. 2012; Brimelow et al. 2017; Trapp et al. 2019). For mPING and CoCoRAHS to develop into this level of climatological resource likely means that the best approach into the future will be recruitment of additional observers as well as dedicated support. As the observer density increases, fewer events will “slip between the gaps.” Acknowledgments. Funding was provided for K. Elmore by NOAA/Office of Oceanic and Atmospheric Research under NOAA–University of Oklahoma Cooperative Agreement NA21OAR4320204, U.S. Department of Commerce. J. Allen acknowledges funding support from the National Science Foundation (AGS-1945286). Publisher Copyright: {\textcopyright} 2022 American Meteorological Society.",
year = "2022",
month = aug,
doi = "10.1175/WAF-D-21-0156.1",
language = "English",
volume = "37",
pages = "1357--1369",
journal = "Weather and Forecasting",
issn = "0882-8156",
publisher = "WEATHER AND FORECASTING",
number = "8",
}