When Hurricane Katrina hit Louisiana on August 29, 2005, surges of seawater more than 20 feet higher than normal tide levels crested over the levees surrounding New Orleans. Within hours, the levees started to fail, flooding 80 percent of the city. More than 1,800 people across several states died in the storm or its aftermath, and thousands of homes and businesses were destroyed. The economic losses totaled more than $100 billion in 2020 dollars, and experts estimate that private insurance covered just $40 billion to $55 billion of the damage.