Heat Wave Magnitude Index

An index proposed in 2014 to rank heatwaves, largely based on a comparison of daily maximum temperatures with those of an earlier period. Heatwaves are grouped into seven categories, the worst being “ultra extreme” with HWMI's over 32, “super extreme” with HWMI's over 16, and “very extreme,” HWMI over 8. No such heatwaves have yet been observed. The Russian heatwave of 2010, which caused an estimated 55,000 excess human deaths, received an HWMI of 5.43. The 2003 European heatwave (~7000 deaths) has an HWMI of 3.48, and the 1980 heatwave in the United States of 4.10.

Simone Russo, Alessandro Dosio, Rune G. Graversen, Jana Sillmann, Hugo Carrao, Martha B. Dunbar, Andrew Singleton, Paolo Montagna, Paulo Barbosa and Jürgen V. Vogt.
Magnitude of extreme heat waves in present climate and their projection in a warming world.
Journal of Geophysical Research: Atmospheres, (accepted 24 October 2014).
doi: 10.1002/2014JD022098

resources

S. E. Perkins and L. V. Alexander.
On the measurement of heat waves.
Journal of Climate, vol. 26, issue 13, pages 4500–4517 (July 2013).
doi: 10.1175/JCLI-D-12-00383.1

A critique of previous measures of heatwaves.