Nonmeteorological scatter, including debris lofted by tornadoes, may be detected using the polarimetric radar variables. For the 17 months from January 2012 to May 2013, radar data were examined for each tornado reported in the domain of an operational polarimetric Weather Surveillance Radar-1988 Doppler (WSR-88D). Characteristics of the tornadic debris signature (TDS) were recorded when a signature was present. Approximately 16% of all tornadoes reported in Storm Data were associated with a debris signature, and this proportion is shown to vary regionally. Signatures were more frequently seen with tornadoes that were rated higher on the enhanced Fujita (EF) scale, with tornadoes causing higher reported total property damage, with tornadoes that were closer to the radar and thus intercepted by the beam at lower altitude, and associated with tornadoes with greater total pathlength. Tornadic debris signatures were most common in spring, when more strong tornadoes occur, and in autumn, when natural debris is more available. Debrissignature areal extent is shown to increase consistently with EF-scale rating and tornado longevity. Vertical extent of a TDS is shown to be greatest for strong, long-lived tornadoes with large radii of damaging wind. Land cover is also shown to exhibit some control over TDS characteristics-in particular, a large percentage of tornadoes with substantial track over urban land cover exhibited a TDS and do so very quickly after reported tornadogenesis, as compared with tornadoes over other land-cover classifications. TDS characteristics over grassland and cropland tended to be similar.

Few studies show how university students perceive and respond to tornado warnings. Lacking in the literature are investigations of what influences perceptions of tornado risk among this population and how these perceptions may influence actions. Through an online survey of 640 undergraduates enrolled at a large university in Nebraska, significant relationships were found between student demographics, perceptions, and response actions. Tornado mythology relevant to the local city influenced perceptions so that students felt the city was less at risk than surrounding rural land. Confirming risk before sheltering remained popular, with some students choosing to never seek shelter during a warning. International students were more likely to initially seek shelter during a warning but had difficulty interpreting warning polygons or accurately choosing the best safety actions. Tornado-related education resulted in international students being more likely to have safety plans and shelter in more appropriate locations. Most domestic students correctly identified safe areas in which to shelter, but fewer knew the precise meaning of a tornado warning polygon. Parents/guardians and the school were the most popular tornado knowledge sources for domestic students, while friends and self-education were popular with international students. Respondents seemed willing to learn more about tornadoes and perceived a lack of tornado-related resources available on campus. This implies that more thorough tornado education and information dissemination on university campuses is warranted. Faster personalization of risk, dispelling local myths, and educating those new to tornado-prone locations should be emphasized.

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