Comparison of Near-Surface Wind Speed Estimation Techniques Using Different Damage Indicators from a Damage Survey of Naplate, IL EF-3 Tornado

Abstract

Estimation of tornado wind speed can be extremely difficult, especially near the ground where tornado damage occurs. Because of limitations of in situ measurements, ground-based damage surveys continue to be the most commonly used method to estimate the near-surface wind speed. This study discusses a comprehensive damage assessment of Naplate, Illinois (IL) tornado that occurred in February 2017. The damage survey included the following damage indicators: residential buildings, trees, and traffic signs. Additional data from social media images were collected and used to supplement the damage assessment. This comprehensive data set of damage indicators was used to estimate the characteristics of the Naplate, IL tornado. Multiple wind-speed estimation methods, each suited to a subset of the damage indicators, were applied to estimate the near-surface wind field of the tornado. The results from all independent methods were compared to create a cross-validated estimation of the surface tornado wind field. The similarity between estimates derived from different damage indicators and methods increases confidence in the wind speed estimation and validates the independent application of any of the methods presented, with each being appropriate for given circumstances and data availability.