This article examines the impact of Hurricane Katrina on the infrastructure of the City of New Orleans. Hurricane Katrina set in motion a devastating series of failures in the critical infrastructure of the City of New Orleans and the surrounding region. The authors argue that Katrina can be viewed as a "normal" disaster involving the complex interaction of interdependent infrastructures resulting in the unanticipated failure of multiple infrastructure systems. Key characteristics of infrastructure interdependencies are explored in relation to the case of Hurricane Katrina and New Orleans. Understanding the nature of normal disasters and the tight coupling of infrastructure systems provides infrastructure managers with important lessons. These lessons involve the need for risk and vulnerability assessment; coordination, cooperation, and communication; and the need for flexible response to disasters.