During a disaster, conventional communications infrastructures are often compromised, which prevents local populations from contacting family, friends, and colleagues. The lack of communication also impedes responder efforts to gather, organize, and disseminate information. This problem is made worse by the unique cost and operational constraints typically associated with the humanitarian assistance and disaster relief (HADR) space. In response, we present a low-cost, scalable system that creates a wide-area, best-effort, ad-hoc wireless network for emergency information. The Communication Assistance Technology over Ad-Hoc Networks (CATAN) system embraces the maker and do it yourself (DIY) communities by leveraging open-source and hobbyist technologies to create cheap, lightweight, battery-powered nodes that can be deployed quickly for a variety of operations. CATAN enables geographically separated users to share information on standard interfaces, i.e. web and SMS, over commonly-used communication interfaces, i.e. GSM and Wi-Fi. These interfaces enable CATAN to accommodate a variety of digital devices while leveraging the global ubiquity of cellular devices. By emphasizing simple, mature, technologies, CATAN avoids many problems that hinder many general purpose ad-hoc technologies. We have tested our infrastructure in a variety of environments and have open-sourced the entire project to encourage collaboration with the greater HADR community..