Within most significant situations, there are often numerous root causes, such as structural failures, inadequate supervision, procedures not followed and unverified assumptions. The root cause behind the death and destruction of Hurricane Katrina, for instance, was not the natural disaster itself, but rather a culmination of things.
One detrimental problem with Hurricane Katrina was the deaths due to drowning. These were caused by an inept levee system and a poor evacuation process. The root causes behind the broken levee system include that some flood walls were not built high enough, the requirements for safety in the design of the system were too low, the system was incomplete and the pump design dimensions were too low.
One of the root causes behind the ineffective evacuation procedure entailed insufficient buses and licensed drivers to evacuate the 100,000 people who relied on public transportation. Moreover, evacuation orders were issued only 19 hours before the hurricane made landfall, yet the evacuation staging plan mandated 30 hours.