Thinking outside the Polygon: A Study of Tornado Warning Reception outside of Warning Polygon Bounds

When the National Weather Service (NWS) issues a tornado warning, the alert is rapidly and widely disseminated to individuals in the general area of the warning. Historically, the assumption has been that a false negative reception (i.e., when someone located within a warning polygon does not receive a tornado warning) carries a higher cost than a false positive reception (i.e., when someone located outside the warning area believes they have received a warning). While many studies investigate tornado warning false alarms (i.e., when the NWS issues a tornado warning but a tornado does not actually occur), very little work focuses on studying individuals outside of the warning polygon bounds who believe they received a warning (i.e., false positive receptions). This work attempts to quantify the occurrence of false positive receptions and possible factors associated with the rate of occurrence. Following two separate storm events, Oklahomans were surveyed about whether or not they received a tornado warning and then their geo-located responses are compared to issued warning polygons. Individuals closer to tornado warnings or within a different type of warning (e.g., severe thunderstorm warnings) are more likely to report a false positive reception than those farther away or outside of other hazard warnings. Further work is needed to understand the rate of false positive receptions across different hazards and how this may influence warning response and trust in the National Weather Service.