During a large-scale disaster, smooth information distribution and sharing between Prefectural and Local Disaster Volunteer Headquarters is crucial in enabling local social welfare councils to conduct efficient disaster-relief activities. Disruption of communication lines and blackout are common during large-scale disasters, which would disable high-speed Internet connection. We have developed a light-weight information sharing system for Shizuokaken Disaster Volunteer Headquarters. This system operates on a cloud server, and its files are light. Because it is a text-based system, the communication volume is small and suitable for narrowband communications, such as satellite telephone. This system is already in practical use at Shizuokaken Council of Social Welfare.