The report continued, "In the aftermath of a major catastrophe, when the memory of the destruction and chaos is still fresh, is the best time to commit to maintain transparency in providing regularly updated risk information."

New Orleans flood threat is rising because the city is sinking rapidly into its base of delta sediment, sea levels are rising and hurricanes with storm surge are increasing, which will "significantly raise the risk of flooding in the city through the 21st century, the report said.

The report noted that storm surge floods in New Orleans in 1915, 1947 and 1965 were followed by only modest improvement in flood defenses as thousands of new buildings were put up in flood plans.

To avoid the cycle of flood and build "the strategy for the rebuilding and development of New Orleans must now be informed by proper assessment of the flood risk--not only the risk today but what it will be in the future," wrote the report authors Patricia Grossi and Robert Muir-Wood.

The report advised that the flood risk can be quantified with catastrophe models which allow the individual components of risk (hazard, exposure, vulnerability) to be separated, "so that uncertainties are explored along with alternative strategies for risk mitigation."

It also considers the role of insurance, the planning process, and the government in providing physical and economic protection so those living and investing in the city can have confidence that the flood risk is being effectively managed.

"While this report concerns a single city along the U.S. Gulf Coast, the devastation caused by storm surge and flooding in New Orleans can be seen as a parable of our time," said Hemant Shah, president and chief executive officer of RMS.

He added that, "These problems are shared by many cities along the U.S. Atlantic and Gulf Coasts, as well as other coastal cities around the world that face similar risks due to rising sea levels and increasing storm intensity associated with climate change."

The report discusses how the risk analysis involved in assessing insurability can be a useful tool for policy makers concerned with determining acceptable levels of risk.

Robert Muir-Wood, RMS chief research officer, said, "New Orleans has the opportunity to pioneer solutions that maintain the viability of the city while at the same time ensuring that risk to the city's citizens and businesses is maintained below acceptable and published thresholds."

He said his company will work to ensure that "probabilistic risk analytics continue to remain at the heart of decisions about development, flood protection, and economic viability."