This paper analyzes special problems faced in disasters by institutions that have custodial responsibility for human beings. Hospitals in New Orleans did not evacuate in advance of Katrina, but the flooding that followed the hurricane made it essential that many hospitals be evacuated. Based on interviews and public sources of information, we describe hospitals' experiences in the days that followed the hurricane and lessons for hospitals in circumstances in which evacuation may arise. Many types of patients present distinct challenges in evacuation circumstances. Planning by individual hospitals is essential but inadequate in circumstances in which multiple facilities are affected.