Supercell tornadoes are much stronger and wider than damage-based ratings indicate

Abstract

Tornadoes cause damage, injury, and death when intense winds impact structures. Quantifying the strength and extent of such winds is critical to characterizing tornado hazards. Ratings of intensity and size are based nearly entirely on postevent damage surveys [R. Edwards et al., Bull. Am. Meteorol. Soc. 94, 641–653 (2013)]. It has long been suspected that these suffer low bias [C. A. Doswell, D. W. Burgess, Mon. Weather Rev. 116, 495–501 (1988)]. Here, using mapping of low-level tornado winds in 120 tornadoes, we prove that supercell tornadoes are typically much stronger and wider than damage surveys indicate. Our results permit an accurate assessment of the distribution of tornado intensities and sizes and tornado wind hazards, based on actual wind-speed observations, and meaningful comparisons of the distribution of tornado intensities and sizes with theoretical predictions. We analyze data from Doppler On Wheels (DOW) radar measurements of 120 tornadoes at the time of peak measured intensity. In striking contrast to conventional damage-based climatologies, median tornado peak wind speeds are ∼60 m⋅s−1, capable of causing significant, Enhanced Fujita Scale (EF)-2 to -3, damage, and 20% are capable of the most intense EF-4/EF-5 damage. National Weather Service (NWS) EF/wind speed ratings are 1.2 to 1.5 categories (∼20 m⋅s−1) lower than DOW observations for tornadoes documented by both the NWS and DOWs. Median tornado diameter is 250 to 500 m, with 10 to 15% >1 km. Wind engineering tornado-hazard-model predictions and building wind resistance standards may require upward adjustment due to the increased wind-damage risk documented here.

Long‐term effects of a tornado: Impacts on woody native vegetation and invasive Amur honeysuckle (Lonicera maackii) in an urban forest

“…Changing atmospheric convection processes associated with climate change in the United States have contributed to more extreme temperatures and more variable precipitation which may be contributing to recent increases in windstorm frequency and intensity (Berz, 1993 ; Karl et al., 1996 ; Moore, 2017 ). For example, the number and variability of tornadoes and supercell hurricanes increased drastically from 1995 to 2006, with further increases in number and intensity during 2012–2017 (Brooks et al., 2014 ; Changnon, 2009 ; Cody et al., 2017 ; Emanuel, 2017 ; Moore, 2017 ; Rahmstorf, 2017 ; Wurman et al., 2021 ). Unfortunately, urban sprawl and built environments, particularly in densely populated metropolitan areas, also have increased the risk of tornado damage (Rosencrants & Ashley, 2015 ).…”

Assessment of the Impacts of Thunderstorm on Flight Operations at Murtala Mohammed International Airport, Ikeja, Lagos State, Nigeria

“…Supercells have a two-to-six hour lifespan [6,16] . They are the storms that are most likely to cause noticeable wind and hail damage as well as strong tornadoes [17] .…”