Tropical Storm Isaac keeps interesting company — it’s an “I” storm. Over the past 11 years, the World Meteorological Organization (WMO) retired seven of the “I” names because of the insured and economic losses those weather events caused, making this one of the most dangerous letters in the hurricane community.

Five of the seven storms with retired “I” names together caused insured property losses of $26 billion. Although the impact at landfall for some of these storms was limited, WMO retired their names because of the intensity they reached at some point. Hurricane Igor resulted in $70 million in insured losses on the eastern Canadian coast in 2010, according to Property Claim Services (PCS) estimates. Estimates are not available for Hurricane Iris, which struck Central America. Hurricane Isabel, however, which hit the Chesapeake Bay region of the United States, reached Category 5 strength at one point when it was northeast of the Antilles.

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The following table lists the retired storms and the impact of each, noting PCS estimates of insured property damage.