In August 2005, Hurricane Katrina made landfall as a Category 3 storm with maximum winds of 125 mph, according to the National Oceanic and Atmospheric Administration. The cost of the ensuing damage to New Orleans and the Gulf Coast was more than $80 billion; it is generally considered to be most destructive tropical storm in U.S. history in terms of property damage, followed by Hurricane Andrew in 1992 and Hurricane Ike in 1998.
Several factors could be involved: First, climate change could be increasing the frequency and severity of such extreme weather events. In addition, as human population continues to increase and coastal development continues, more and more valuable assets are built in what is effectively harm’s way.
A 2008 study in Natural Hazards Review, a journal of the American Society of Civil Engineers, “Normalized Hurricane Damage in the United State: 1900-2005,” analyzes storm-related property damage figures from 1900 through 2005 adjusted (“normalized”) for inflation, wealth and population factors over time.
The report findings include:
- Adjusted for inflation, population, and wealth, hurricane-related damages steadily increased from 1900 to 2005.
- Based on the adjusted data, Hurricane Katrina is the second-most destructive storm in U.S. history. The top-ranking storm in terms of property damage is the Great Miami Hurricane of 1926, with losses between $140-157 billion in 2005 dollars.
- While 1996-2005 was the second-most costly period for storm-related damages, the preceding periods of 1976-1985 and 1986-1995 were “anomalously benign,” accounting for only 10% of all storm damage reported since 1900.
- “The years 2004 and 2005 stand out as particularly extreme, with 7 of the top 30 most damaging (normalized) storms of 106 years. No other 20-year period has more than 3 top 30 storms.”
- Approximately 85% of all storm-related damages occur in the months of August (35%) and September (50%).
The researchers conclude that “as people continue to flock to the nation’s coasts and bring with them ever more personal wealth, losses will continue to increase,” and suggest that action be taken to address the rising populations in hurricane-prone coastal areas.