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Two independent datasets (total n = 959) of tornado-stricken passenger vehicles collected from 12 tornado events over a 15-yr time span are combined and tested to determine whether vehicle movement and/or upset are consistent at various wind speed intensities. Impacted vehicles are classified into three categories of upset motions (no movement, lateral shifting, rolling and lofting motions) for each wind intensity category of the Fujita and Enhanced Fujita scales. Vehicles observed by Schmidlin exposed to F1 and F2 winds are statistically assessed to determine if upset distribution values are consistent with those assessed by Marshall at these respective wind speeds; this same approach is subsequently conducted for vehicles at F3/EF3 and F4/EF4 winds. No statistical differences are found between the two sets of field survey data, which are therefore considered to be of the same population. Passenger vehicles are currently not utilized as damage indicators for rating tornado wind intensities, although the results of this study suggest that only 10% of vehicles are typically shifted at EF0 wind speeds, 36% are displaced at EF1 and EF2 winds (5% are rolled or lofted), 63% are displaced at EF3 and EF4 winds (15% are rolled and lofted), and all vehicles exhibit some form of movement or upset at the EF5 wind speed. The results of this study may potentially serve as a basis for providing better tornado safety protocols, designing safer vehicles and infrastructure, and estimating tornado wind speeds where few EF-scale damage indicators are available.

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Most building damage occurs at relatively low wind speeds, at or below 50 m s–1 (112 mph), as certain components fail, such as doors, windows, chimneys, and roof coverings. Rainwater then enters these openings, leading to interior damage. Structural failures usually begin with the removal of gable end walls, roof decking, and poorly attached roof structures as wind speeds increase; the greatest damage occurs at roof level as wind speeds increase with height above the ground. Internal wind pressure effects can lead to additional, more catastrophic damage, such as the removal of walls and ceilings. It is difficult to measure wind speeds directly on buildings as they would have to be instrumented well in advance of the storm, and there is no guarantee the storm would strike them. Furthermore, flying debris can damage pressure sensors on instrumented buildings. Thus, damage evaluators must infer failure wind speeds indirectly by studying damage left behind in the wake of windstorms. Therefore, it is important that damage evaluators know how buildings are constructed to better understand how they fail. This chapter identifies similar failure modes in residential structures regardless of wind type according to information from more than four decades of storm damage surveys. The information presented herein highlights some of the lessons learned in evaluating storm damage to wood-framed residential structures.