We evaluate effects of low socioeconomic position (SEP) and social networks among Black Hurricane Katrina victims on access to and processing of evacuation orders, and abilities to evacuate before the storm hit. We also explore whether SEP, moderating conditions, and communication outcomes affected risk perceptions of the storm's severity and compliance with evacuation orders. We conducted stepwise logistic regression analyses using survey data collected in September 2005 among Black respondents in shelters throughout Houston, TX. Having few social networks, being unemployed, and being of younger age were significantly associated with having heard evacuation orders and whether victims' perceived having heard clear orders. This study provides implications for targeted public health emergency campaigns and future research to understand the effects of sociodemographic influences on communication inequalities and public health preparedness.