Disaster warning messages: challenges and opportunities based on Brazil's experience

This research investigates the effectiveness of disaster communication messages in Brazil, with a focus on the structure and content of SMS messages sent out from 2018 to 2023. The Warning Response Model was used for coding. The analysis reveals that only 1.83 % of the 73,701 messages analyzed were complete; that is, they contain all the elements to be effective (source, hazard, location, guidance and time). The results also show that messages about natural hazards achieved the highest scores and that the states of Santa Catarina and Paraná stand out. In contrast, states such as Minas Gerais and Goiás achieved low scores regarding messages about technological risks. In addition, lacking geographical and time specifics, and failing to include details on the potential impacts compromise the effectiveness of the messages. The study highlights that the message length limit of 160 characters is an obstacle to effective communication, which can compromise the population's perception of risk, its adoption of protective actions. The research concludes that optimizing disaster communication messages is crucial to improve disaster response in Brazil, while it recommends using a multichannel system, the continuous training of civil defense agents, and greater community engagement to strengthen resilience. • Low completeness in disaster SMS messages • Geographical disparities in message effectiveness • Lack of critical details • Message length limitation