Dating Hail: Investigation and Determination of the Date of Occurrence of Hail Impact Damage

Hail impact can damage roof coverings, building exteriors, and exterior equipment and appurtenances. Following a hail event, evaluations to determine the extent of hail impact distress are common. However, many buildings experience multiple hail events over their service life and, in some cases, it is necessary to delineate the extent of damage from different hail events. Weather data resources are useful to determine the dates of reported hail occurrences and the reported or estimated hail sizes in the vicinity of a given site. However, data collected during a site investigation provides valuable, site-specific information, and such an investigation is necessary to evaluate a building for damage related to hail impact. Determination of damages caused by a specific hail event (or events) requires even more extensive site investigation. This paper discusses data collection and site investigation methodologies utilized to determine the date of occurrence for hail impact damage. Case studies are presented to illustrate useful investigative techniques and to provide examples of data collection used to determine the date of hail occurrence.