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Walker S. Ashley, Andrew J. Krmenec, and Rick Schwantes

1. Introduction Nocturnal tornadoes appear to be particularly hazardous to humans as evidenced by recent killer tornadoes ( Table 1 ) and tornado outbreaks. As an example, 80 tornado fatalities occurred during 2007, with 59 (or 73.8%) of those fatalities taking place between sunset and sunrise; moreover, 19 of 26 (or 73.1% of) 2007’s killer tornadoes occurred at night. Nocturnal tornado events enhance human vulnerability and reduce the success of mitigation activities for several reasons. First

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Ariel E. Cohen, Joel B. Cohen, Richard L. Thompson, and Bryan T. Smith

1. Introduction Recent significant advances have occurred in the meteorological community’s ability to reproducibly evaluate and quantify the threat for tornadoes. In an age of increasing need for accurate, high-precision forecasts, this work is becoming increasingly integrated into daily National Weather Service operations. Smith et al. (2012) and Thompson et al. (2012) laid the initial groundwork for relating storm-scale characteristics and near-storm environments to tornado damage

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Walker S. Ashley

1. Introduction and background Tornadoes are nature’s most violent windstorms and are a significant hazard to life and property throughout the United States. Approximately 800–1400 tornadoes are reported in the United States in any given year, with only a small percentage of these events producing casualties. Although there have been numerous advances in tornado detection, warning dissemination, and public awareness, tornado casualties cannot be prevented entirely as evidenced by recent

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James B. Elsner, Tyler Fricker, Holly M. Widen, Carla M. Castillo, John Humphreys, Jihoon Jung, Shoumik Rahman, Amanda Richard, Thomas H. Jagger, Tachanat Bhatrasataponkul, Christian Gredzens, and P. Grady Dixon

1. Introduction A tornado is a rotating column of air swirling upward from the surface and extending from a cumuliform cloud. The strongest tornadoes develop under rotating thunderstorms (i.e., supercells). Not all supercells produce tornadoes. This fact suggests that tornado initiation is sensitive to an interplay of many processes across a range of spatial scales, including the scale of a few kilometers at which the flow is described as a converging, swirling plume ( Lewellen et al. 2000

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Abdullah Kahraman and Paul M. Markowski

1. Introduction This paper presents what is believed to be the most comprehensive climatology of tornadoes in Turkey to date. [The only other known compilation is available on the Turkish Meteorological Services Web page (in Turkish) at http://www.dmi.gov.tr/FILES/arastirma/afetler/hortum.pdf . It consists of 31 tornadoes recorded between 1940 and 2010.] The climatology spans the years 1818–2013. Tornado climatologies recently have been published for several European countries, including

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Jenni Rauhala, Harold E. Brooks, and David M. Schultz

1. Introduction As late as the mid-1990s, Finnish meteorologists generally assumed that severe convective storms or tornadoes did not occur in Finland and, if they occurred, they were rare. Tornado reports were not collected, and no research on severe convective storms was published from the 1960s until recently. However, since 1997, severe thunderstorms, and especially tornadoes, have received a lot of media attention in Finland. Thus, Finnish meteorologists have started to appreciate the

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James B. Elsner, Tyler Fricker, and William D. Berry

1. Introduction Nearly one-fifth of all natural-hazard fatalities in the United States are the direct result of tornadoes ( National Oceanic and Atmospheric Administration 2015 ). A tornado that hits a city is capable of inflicting hundreds or thousands of casualties (death or injury). Data from the Storm Prediction Center of the National Oceanic and Atmospheric Administration show that the 27 April 2011 Sawyerville–Eoline, Alabama, tornado produced 1564 casualties, with 64 of them resulting in

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Kevin M. Simmons and Daniel Sutter

1. Introduction Tornadoes in the United States have become less deadly over the past 75 yr, with the annual national tornado fatality rate declining from 1.8 per million residents in 1925 to 0.11 per million in 2000 ( Brooks and Doswell 2002 ). The National Weather Service’s (NWS’s) efforts to issue more accurate, reliable, and timely tornado warnings and to educate the public about tornado safety have surely contributed to this reduction. Conventional wisdom suggests that NWS warnings explain

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Ernest M. Agee

1. Introduction and considerations The first proposed tornado taxonomy was presented by Agee and Jones (2009 , hereafter AJ) consisting of three types and 15 species, ranging from the type I (potentially strong and violent) tornadoes produced by the classic supercell, to the more benign type III convective and shear-driven vortices such as landspouts and gustnadoes. This original taxonomy was presented to (i) help organize and sort out the variety of tornado occurrences, with different roles

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Amanda K. Kis and Jerry M. Straka

1. Introduction Nocturnal tornadoes are defined as occurring between sunset and sunrise. They compose only about a quarter of observed tornadoes, yet account for over 40% of tornado casualties ( Ashley 2007 ). This dichotomy was recently made very apparent during the active year of 2008, throughout which nocturnal tornadoes accounted for many injuries and fatalities that included 23 deaths by a single enhanced Fujita scale 3 (EF3) tornado in Tennessee during the Super Tuesday outbreak on 5

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