Understanding Hail in the Earth System

Abstract

The processes leading to the development of hail and the distribution of these events worldwide are reviewed. Microphysical and physical characteristics of hail development are described to provide context of the notable gaps in our understanding of what drives hail to grow large, or what determines how it falls to the ground. Distributional characteristics of hail are explored, utilizing both surface observations of hailstones and remotely sensed observational data sets to identify opportunities and needs for new observations. These observational deficiencies contribute to our limited capacity to both forecast hail or its expected size and reduce the effectiveness of using favorable conditions for hail development as a proxy to frequency where observations are unavailable. Given the substantive influences of both climate variability and the changing Earth system on hail, the latest understanding of their contributions to risk are addressed. Applying this understanding of the distribution and physical characteristics of hail, the damage by hail to agriculture and insured property is assessed. Much remains unknown about the processes leading to hail growth and environmental controls on hail occurrence, size, and magnitude, particularly outside of the United States and Europe. A better understanding of the global occurrence of hail is also needed to better anticipate the hazard and associated impacts.

Review article: Natural hazard risk assessments at the global scale

“…However, as insurance companies have to either provide the solvency capital for rare events (e.g. 200-year return period event according to the EU Solvency II directive in Europe) or have to reinsure their risk, there is a growing and large demand to better estimate the risk related to the different SCS sub-perils in a scientific manner (Allen et al, 2019). The few existing models owned by the insurance market quantify the risk mainly on a regional (e.g., Schmidberger, 2018a), national, or continental level (e.g., Punge et al, 2014).…”

Agricultural Perspectives on Hailstorm Severity, Vulnerability, and Risk Messaging in Eastern Colorado

“…Hailstorms generally occur east of the Rocky Mountains, with a corridor of maximum activity in the Great Plains, from Texas northward through Nebraska ( Fig. 1; Allen and Tippett 2015). Within this area of enhanced hail activity, eastern Colorado has experienced some particularly damaging hailstorms in recent years.…”

“…Economic impact from U.S. hailstorms continues to rise and now commonly exceeds tens of billions of dollars annually; in some cases, a single hailstorm can be a billion-dollar disaster if it strikes a major metropolitan area (Prein and Holland 2018; Rocky Mountain Insurance Information Agency 2019). The environments supportive of hailstorms are relatively wellknown, as are climatological statistics such as frequency, seasonality, and spatial distribution (Changnon 1977;Changnon and Changnon 2000;Allen and Tippett 2015;Allen et al 2015;Lepore et al 2018;Allen et al 2020). Less understood are the human perceptions of and responses to hailstorms and their associated impacts.…”

“…(25.4 mm)] tend to lead to the most physical damage, socalled plowable hailstorms, in which hail accumulates to appreciable depths and requires snow plows for its removal, can also cause substantial damage and travel interruptions across Colorado (Kalina et al 2016;Friedrich et al 2019). The eastern half of Colorado has seen an increasing trend in hail reports at all size thresholds since 1997 (Childs and Schumacher 2019), an era in which severe weather data are more reliable because of standardized reporting practices and implementation of Doppler radar (Agee and Childs 2014;Allen and Tippett 2015). This increasing trend is in contrast to national-level hail trends, which were essentially flat over the period 1997-2014 (Allen and Tippett 2015).…”

“…The eastern half of Colorado has seen an increasing trend in hail reports at all size thresholds since 1997 (Childs and Schumacher 2019), an era in which severe weather data are more reliable because of standardized reporting practices and implementation of Doppler radar (Agee and Childs 2014;Allen and Tippett 2015). This increasing trend is in contrast to national-level hail trends, which were essentially flat over the period 1997-2014 (Allen and Tippett 2015). There also exists an increasing proportion of 2.01-in.…”