“Hurricane Katrina made landfall on August 29, 2005, in southeastern Louisiana, with maximum sustained winds of 140 mph. ... Coastal storm surge flooding of 20 to 30 feet above normal tide levels, along with large and dangerous battering waves, occurred near and to the east of where the center of the storm made landfall.” -fema.gov
Thats just a summary of what happened. If you would like a similar, but differently worded overview, you can search up “hurricane Katarina overview”