With flash floods in Louisiana this week, many Americans are wondering if they are at risk.

A recent report shows that 5 million Americans living on the United States coast lines are at risk of increased flooding. These threats could last for the next 30 years.

The combination could raise sea levels during storms to 4 feet above the high-tide line, threatening property that contains 2.6 million homes on 3 million acres of land, according to the report released Wednesday by Climate Central, a nonprofit research and journalism organization based in New Jersey.

“Escalating floods from sea level rise will affect millions of people, and threaten countless billions of dollars of damage to buildings and infrastructure,” Climate Central’s Ben Strauss, the lead author of the report, said in a statement…

[The report] says the odds of once-in-100-years flooding hitting regions of the coastal U.S. have more than doubled. (Read the CNN article.)

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According to the report, the states that are at the largest risk for flooding are Florida, Louisiana and New York. New Orleans tops the list of flood-prone cities. The report mentions that 284,000 people are susceptible to damage in the Big Easy.

By 2030, storm surges combined with rising seas could raise waters to 4 feet (1.2 metres) or more above high tide lines at many locations, the reports said, noting that 4.9 million people live in 2.6 million homes in this vulnerable zone between the observed high tide and the top of expected flood waters.

Cities are likely to be hit hardest, Strauss said, with 90 percent of the impact projected to come in areas with extremely dense population.

In 285 coastal cities and towns, more than half the population lives below the 4-foot mark, the Climate Central report found. Florida has 106 of these at-risk municipalities; Louisiana has 65, New Jersey and North Carolina have 22 each, Maryland has 14, New York has 13 and Virginia has 10. (Read the Huffington Post article.)

More than 500 U.S. cities have at least 10% of the population at increased risk, the studies said. (Read the Detroit Press article.)

Obviously, the cost of such damage would be catastrophic. The report estimates that $30 billion in southeast Florida alone would be at risk!

If you’d like to check out what the report says about flood risk in your area, visit their interactive map.