La Niña means a greater frequency of damaging storms and more damage per storm.
During cold events in the eastern Pacific, the odds are significantly higher that the U.S. will experience greater impacts because of a larger number of tropical cyclones and higher intensities for each storm. Over the 73 years covered by this st udy, the total numbers of tropical storms and hurricane landfalls were 58 during El Niño years versus 82 during La Niña years. The average Saffir/Simpson category of landfalling tropical cyclones (counting tropical storms as zero) is 0.93 du ring El Niño years and 1.33 during La Niña years. This translates to a modest, but significant (at the 94% level), difference of about 6 m/s in wind speed (from 30.6 to 36.3 m/s). Because damage increases with at least the square of wind s peed (Pielke and Landsea 1998), the greater intensity translates to a substantial increase in damage. The average damage per storm in El Niño years is $800 million vs. $1,600 million in La Niña years. Because the relation of ENSO and hurri cane damage is quite similar to climatological variations (Gray 1984a; Bove et al. 1998), it supports claims that a normalization methodology can account for societal change to provide useful climatological information (Pielke and Landsea 1998).