More than two years after the event we do not yet know how many people died as a result of Hurricane Katrina. The number to die during the storm, in the storms path is clear. It is likely though that many more people died after evacuation as a result of the storm. No standard definitions exist to guide the analysis of such events. Many likely died due to aggravation of preexisting conditions, and many others reportedly succumbed to changes in medical care or the unavailability of medications after evacuation. One report suggests that all cause mortality could have risen as much as 47% in the first six months of 2006. Anecdotal evidence suggests that mortality rates continue to be above pre-Katrina levels. All mortality threats were and continue to be greatest among the poor and elderly.

We are estimating uncounted victims with a novel approach, created via an open access interactive Web tool that allows individuals to provide information on the dead. It can be found at http://www.katrinalist.columbia.edu/. We crosscheck the list with those official records we have been able to obtain from relevant state authorities. In this way we generate a profile of deceased victims who typically emerge as poor, underserved, elderly, isolated, suffering illness, lacking a car and distrustful of formal authority. Social status and livelihood determined social vulnerability and mortality risk, especially in areas of concentrated poverty in New Orleans.

The total mortality can be estimated in a range from a minimum being those direct victims recoded in official statistics to a maximum that includes all plausibly related and long-term victims. The latter may be as much as double the official figure.