Relationships Between Storm Mode, Tornado Warning Outcomes, and Social Vulnerability

This study is the first of its kind to assess convective storm mode in relation to social vulnerability and tornado occurrence. Specifically, we examine the connections between tornadic storm modes, tornado warning outcomes, and social vulnerability within the context of National Weather Service (NWS) county warning areas (CWAs) east of the Continental Divide. Radar data, tornado warnings, and tornado reports were gathered from 2007 to 2017 to illustrate spatiotemporal patterns in storm mode types, false alarms, lead time warnings, and missed events. Tornadic storms were classified into categories based on radar reflectivity characteristics: discrete, multi-cellular, linear, tropical, or disorganized/other. Results from this study indicate that many areas with elevated social vulnerability experience a wider range of tornadic storm modes, as well as above average tornado false alarm rates. Spatial relationships reveal that CWAs in the southeastern U.S. not only experience more linear and tropical storm modes, but also contain greater measures of social vulnerability. As such, identifying the relationships between storm mode, social vulnerability, and warning outcomes provides a comprehensive understanding of tornado disaster risk at the CWA scale. This information will help NWS weather forecast offices (WFOs) and emergency managers better prepare for tornado threats, as well as assist them with improving or developing new community preparedness and mitigation strategies.