This research introduces a communication system that disseminates tsunami warnings to the community at risk right after an earthquake hits. Its function also aids the existing warning dissemination channels which may be unavailable or be affected by the earthquake. Due to its capability to be powered autonomously and its portability, it has advantages when compared to the existing solutions based on the commercial cellular infrastructure, and it may act as an alternative channel that can stand independently. On top of that the universal use of GSM handsets may help the system reach a significant number of at risk civilians. We ran experiments and analysed the results and have also examined how the system would fit within the existing disaster management operating procedure in Indonesia through data gathering. The proposed system, technically, has adequately fulfilled the user requirements we investigated and has the potential to be incorporated in the existing procedures and synchronised with other existing early warning dissemination channels.