Coastal US at risk from Storm and Rain surge combined, rising sea levels also add to the concernDaniel McCarthy (Author) Published Date : Jul 28, 2015 19:57 IST
After the devastating Hurricane Katrina, the population of New Orleans possibly thought they had gained good knowledge of areas that were susceptible to floods during another storm. Therefore when a significantly weaker storm Hurricane Isaac struck in 2012, people living in the western part of Lake Pontchartrain were not a worried lot since were spared from the raging waters that inundated much of the city when Katrina struck.
But Isaac delivered differently and became a perfect storm for that part of the city. The surge resulting from Isaac pushing ahead took the lake levels higher by about 9 feet and stayed elevated for a longer period than usual. Simultaneously the areas abutting the lake also witnessed 11 inches or more of rain due to the storm. With lake levels so high, the rain water had no place to drain and consequently it flooded the houses and streets on the western side of the lake.
Hal Needham, a storm surge scientist from Louisiana State University stated that many people were caught off guard and people in their thousands were rescued from the waters still rising. It now turns out that several other coastal residents could be facing the meteorological double whammy of storm surge and freshwater flooding which according to a recent study constitutes a serious threat for large stretches across the U.S. coast.
Unfortunately, many places in US do not have a plan for compound flooding though risk studies do examine one danger or the other. And the problem is further exacerbated by the rise in sea level driven by global warming says Needham.
A researcher at University of South Florida, Thomas Wahi noticed that no one really had examined the frequency of compound flooding events along the US coast which holds over half of the nation s population in densely populated pockets witnessing steady rise in development over the recent decades. Wahi with his colleague examined historical data in depth to determine if a relationship could be established between storm surge and heavy precipitation events along the coasts. They observed that in substantial parts of the Atlantic and Gulf coasts witnessed a link between the two factors and compound flooding happened more frequently than any time in the past for several locations.
Wahi added that the focus of the study was to enhance the awareness that these factors do exist and are dangerous. He went on to say that we have so far, nearly ignored them.
Coastal US at risk from Storm and Rain surge combined, rising sea levels also add to the concern