Drowned City: Hurricane Katrina and New Orleans.

Brown, Don. Drowned City: Hurricane Katrina and New Orleans.
August 4th 2015 by HMH Books for Young Readers

Like this author's The Great America Dust Bowl, this is a hugely informative book detailing the events of Hurricane Katrina and its aftermath. Not only is it well researched and complete, but the fact that it is a graphic novel will encourage students to read it. This is a great book to have on hand to go with the tons of fiction books about this event, and it will be very useful in explaining some of the topics. It is not for the faint of heart-- even though it doesn't go into great detail, it is unflinching in the depiction of the large number of fatalities. 

Just a few fiction books on Hurricane Katrina:

Herlong, M.H. Buddy.
Patrick, Denise Lewis. Finding Someplace
Philbrick, Rodman. Zane and the Hurricane: A Story of Katrina
Smith, Tamara Ellis. Another Kind of Hurricane
Woods, Brenda. Saint Louis Armstrong Beach.