Among New Orleans arrestees, pre-Katrina rates of crack and heroin use and market participation was higher than other southern cities, and comparable to New York where both cities sustained a rigorous outdoor drug market. Prior to Katrina, almost every respondent described the illicit markets in New Orleans as very public; numerous persons were reported to be selling several different illegal drugs in almost every neighborhood, for low retail unit prices at any time of the day or week. Almost every subject reported the ability to purchase marijuana, or crack cocaine within a short distance of their home, or even have it delivered to their home. The flooding of New Orleans disrupted the city’s flourishing drug markets, both during and immediately after the storm. Drug supplies were limited, but never completely unavailable. Many subjects reported that they had not used drugs during or after the storm because they were focused on surviving. Just prior to the hurricane, several subjects reported making drug purchases and acquiring stashes for use in the aftermath. Some subjects reported parties and using drugs during the storm. After the flood, while making their way to higher ground, they often took a drug stash. Only a few subjects reported that they had used drugs at the Superdome, but many reported that drug use was common there. Respondents reported that alcohol or drugs were not being used in the Houston Astrodome, but that outside the Astrodome, they were often approached by or could easily locate middlemen and drug sellers. Evacuees could typically access illegal drug markets wherever they went. This analysis includes data from criminal justice sources, and compares it to data on cities where no disaster occurred. The analysis also includes data collected from ethnographic interviews from over 100 New Orleans evacuees recruited in New Orleans and Houston. Tables, references