Historical Hurricane Experience
From 1949 to 1999, 302 hurricanes formed in the Atlantic Basin. [4]4. Throughout this publication, data on the number, tracks, and intensities of Atlantic Basin hurricanes is from the National Hurricane Center (NHC), a unit of the National Oceanic and Atmospheric Administration's National Weather Service. A convenient collection of NHC data — including "best track" and intensity estimates as determined by an analysis of all available data — is available on the Internet in the Unisys Corporation's weather website at weather.unisys.com. [Cited 24 May 2000.] For a more comprehensive analysis of the data through 1986, ISO relied on Charles J. Neumann et al., Tropical Cyclones of the North Atlantic Ocean, 1871-1986: with Storm Track Maps Updated through 1989, Historical Climatology Series 6-2, 3rd rev. (1987; Reprinted, Asheville, N.C.: National Climatic Data Center, 1990). Of those, 78 made landfall in the continental United States, and 31 of the hurricanes that made landfall were "intense." [5]5. The Saffir-Simpson scale rates the intensity of hurricanes based on windspeeds. Meteorologists classify hurricanes with Saffir-Simpson ratings of 3 or more (with sustained winds exceeding 110 miles per hour) as "intense." For each hurricane that made landfall in the United States, this analysis uses the highest Saffir-Simpson rating over land.
Expressed another way, an average of about 6 Atlantic Basin hurricanes occurred each year, 26% of those storms made landfall in the United States, and 40% of the hurricanes that made landfall were intense.
Managing hurricane risk might be less difficult if those averages applied year in and year out. But the number of hurricanes, their tracks, and their intensity vary greatly from year to year.
During the past half century, the annual number of Atlantic Basin hurricanes has been as low as two and as high as twelve. The percentage of such hurricanes making landfall in the United States in a single year has been as low as zero and as high as 86%, in 1985, when six out of seven storms made landfall.
The average Saffir-Simpson rating for Atlantic Basin hurricanes making landfall in a particular year has been as low as 1 and as high as 4.
From 1949 to 1999, catastrophic hurricanes in the United States [6]6. Including Hawaii, Puerto Rico, and the U.S. Virgin Islands. caused direct insured property losses totaling $37.9 billion — or an average of $743 million per year. In fourteen of the years from 1949 to 1999, insurers incurred no losses from catastrophic hurricanes, and losses in one year — 1992 — were as high as $17.1 billion.
But price levels have changed significantly over the last half century. So have the population in areas exposed to hurricanes and the average amount of property owned by each resident of those areas. To illustrate the damage that past storms might do if they were to occur today, ISO adjusted historical losses from catastrophic hurricanes for inflation, population growth, and changes in real tangible wealth. [7]7. ISO used the Consumer Price Index published by the Bureau of Labor Statistics to adjust losses caused by past hurricanes for inflation. ISO obtained population data from the Bureau of the Census and used changes in population of the states affected by each catastrophic hurricane to adjust historical hurricane losses for population growth. From the Department of Commerce, Bureau of Economic Analysis, ISO obtained historical data about the inflation-adjusted value of privately owned structures and durable goods. ISO used that data to adjust historical losses for changes in the amount of property per person.
On this adjusted basis, catastrophic hurricanes from 1949 to 1999 caused an estimated $87.8 billion in insured property losses, or an average of $1.7 billion per year.
Losses due to catastrophic hurricanes have been especially high in recent years. From 1989 to 1999, adjusted losses due to catastrophic hurricanes averaged $4.2 billion per year — almost four times the $1.1-billion-per-year average from 1949 to 1988.
The single catastrophe that caused the most insured property loss in U.S. history is Hurricane Andrew of 1992. According to ISO's Property Claim Services unit, that storm caused an estimated $15.5 billion in insured losses. Adjusted for changes in prices, population, and wealth since then, a hurricane like Andrew might cause $22.9 billion in losses if it were to recur today.
Even excluding the extraordinary losses from Hurricane Andrew, adjusted losses due to catastrophic hurricanes have averaged $2.1 billion per year since 1989 — almost double the $1.1-billion average from 1949 to 1988.
Geographic Distribution of Losses
In the last half century, Florida and Texas have suffered the largest hurricane losses in the Unites States. Based on adjusted losses, 38.0% of the direct insured property losses caused by catastrophic hurricanes occurred in Florida. Another 11.1% of the adjusted losses occurred in Texas.
The bulk of the remaining losses occurred in other coastal states and in Hawaii, Puerto Rico, and the Virgin Islands. But at least six storms — Hurricanes Hazel (1954), Agnes (1972), Eloise (1975), Frederic (1979), Opal (1995), and Fran (1996) — caused losses in inland states, including Kentucky, Ohio, Tennessee, and West Virginia. Those losses amounted to 0.2% of the total adjusted insured losses from catastrophic hurricanes from 1949 to 1999.
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