A deadly tropical storm caused destruction along the Gulf coast – most notably in New Orleans, where hurricane protections catastrophically failed, plunging the city into crisis on this day in 2005.

Hurricane Katrina had formed over the Bahamas on August 23, the result of an interaction of a tropical wave and the remains of a tropical depression. Florida announced a state of emergency on August 24, in advance of the hurricane hitting land – and three days later, President Bush declared a state of emergency in selected regions of Louisiana, Alabama and Mississippi.

Katrina was upgraded to a Category 5 storm, and on August 28 – two days after ignoring federal and state offers of help and a recommendation to evacuate – New Orleans Mayor Ray Nagin ordered a mandatory evacuation, the first in the city’s 300-year history. President Bush declared a state of emergency in Louisiana on the same day.

A man pushes his bicycle through flood waters near the Superdome in New Orleans.

New Orleans’ Superdome stadium (picture above) was opened as a ‘refuge of last resort’, and police instructed all remaining citizens to go to key pickup points to be bussed out of the city. By the evening of August 28, an estimated 80% of New Orleans’ 1.3 million residents had been evacuated or relocated, with tens of thousands of people remaining in their homes or moving to shelters.

The following morning, Hurricane Katrina struck the city. Measuring Level 3, stretching across 400 miles and bringing sustained winds of 100–140 miles per hour, it subjected New Orleans to hurricane conditions for hours.

The city was already at risk, being completely surrounded by water and having an average elevation of six feet below sea level. And before Katrina hit, the National Hurricane Center had aired concerns that a storm surge caused could break New Orleans’ levees – which protected the city from major flooding. On August 29, 53 levees were breached, submerging 80% of the city under water.

Conditions for the 10,000 New Orleanians who had sought shelter in the Superdome quickly deteriorated: water and food supplies ran short, sanitary facilities broke down and the dome itself was significantly damaged by the storm.

Residents wait to be rescued from the floodwaters of Hurricane Katrina

As scenes of desperation continued two days after the hurricane hit, a public health emergency was declared and people began to be airlifted or bussed to safety. However, many displaced residents were without food, water or medical assistance for days after Katrina struck, and floodwaters lingered for weeks. Some survivors and evacuees reported seeing dead bodies lying in city streets and floating in still-flooded sections.  

[Read more: October 15, 1987 - Britain is hit by Great Storm after weathermen tell us 'not to worry']

Homeland Security Secretary Michael Chertoff described the aftermath of Hurricane Katrina as "probably the worst catastrophe, or set of catastrophes" in the country's history.  Government officials – in particular, the Federal Emergency Management Agency (FEMA), led by Michael D. Brown – were widely criticised for their slow response to the disaster.

The hurricane’s final death toll was 1,836. There was one fatality in Kentucky, two each in Alabama, Georgia and Ohio, 14 in Florida, 238 in Mississippi – and 1,577 in Louisiana.