Hurricane Katrina is often referred to as a man-made, rather than natural, disaster by those who fault infrastructure problems for the decimation caused by this storm that ravaged New Orleans and other parts of the Gulf Coast.
On Aug. 26, Katrina looked like a hurricane that was fizzling out, but it began rapidly strengthening to Category 5 levels over warm water in the Gulf. By Aug. 28, a mandatory evacuation order was issued for New Orleans. As the now-Category 3 hurricane reached the city, water topped over its systems of levees causing them to break and the streets to flood. Eventually, 80 percent of the city was underwater [sources: Drye, Brandt].
Katrina left residents who couldn't or chose not to evacuate stranded in their homes with waters rising around them. Forty percent of hurricane-related deaths were from drowning. Slow federal government reaction to the plight of those affected led to claims of incompetence and even deliberate disregard for poor and black people [sources: Treaster, CNN].
In all, Hurricane Katrina claimed 1,833 lives and at $108 billion is considered the costliest hurricane in U.S. history, though 2017's Hurricane Harvey could surpass that amount once the damage is tallied [source: New York Times] . The Federal Emergency Management Agency calls it "the single most catastrophic natural disaster in U.S. history" [source: CNN].
Katrina also displaced 400,000 people to areas like Houston and Atlanta [source: Brandt]. Many never returned to New Orleans. An upgraded system of levees was completed in 2013, but officials are worried about the massive cost of maintaining them with a shrunken tax base [source: Schliefstein].