Some caution on the use of severe wind reports in post-event assessment and research

Aerial and ground surveys of wind damage were conducted immediately following the occurrence of significant quasi-linear convective systems during the Bow Echo and MCV Experiment (BAMEX). The location and scope of the surveys were guided initially using NWS Local Storm Reports (LSRs) and other preliminary information from relevant NWS offices. For most of the BAMEX events, the number and density of severe wind reports correlated poorly with the actual extent and magnitude of the surveyed damage. In one example in a rural area, a 30-km long by 10-km wide swath of F0 (and a smaller, embedded swath of F1) wind damage was represented by two reports near the eastern edge of the damage swath. The event was represented by the same two reports in Storm Data, although the narrative of one of the entries was at least more descriptive in terms of the damage intensity. Counter to this, examples were also found in which large numbers of wind reports were listed in the LSRs (and later in Storm Data) for events that were later deemed relatively weak, based on the post-event surveys. Indeed, many of these reports could never be verified.

The objective of this presentation is to inform researchers and others of problems with assessing the severity of an event(s) based only on LSRs and/or Storm Data severe wind reports. Such problems may have implications on severe wind “climatologies,” hazard models, etc.