title: More tornadoes in the most extreme U.S. tornado outbreaks.
abstract: Tornadoes and severe thunderstorms kill people and damage property every year. Estimated U.S. insured losses due to severe thunderstorms in the first half of 2016 were $8.5 billion (US). The largest U.S. effects of tornadoes result from tornado outbreaks, which are sequences of tornadoes that occur in close succession. Here, using extreme value analysis, we find that the frequency of U.S. outbreaks with many tornadoes is increasing and that it is increasing faster for more extreme outbreaks. We model this behavior by extreme value distributions with parameters that are linear functions of time or of some indicators of multidecadal climatic variability. Extreme meteorological environments associated with severe thunderstorms show consistent upward trends, but the trends do not resemble those currently expected to result from global warming.
authors.affiliation: Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, USA. mkt14@columbia.edu.|Center of Excellence for Climate Change Research, Department of Meteorology, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Tippett
authors.affiliation: Lamont Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA.
authors.forename: Chiara
authors.initials: C
authors.lastname: Lepore
authors.affiliation: Laboratory of Populations, Rockefeller University, New York, NY 10065, USA.|The Earth Institute and Department of Statistics, Columbia University, New York, NY 10027, USA.|Department of Statistics, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Joel E
authors.initials: JE
authors.lastname: Cohen