Abstract: In the context of natural disasters, as one of the key factors affecting the effectiveness of emergency management, the effective reach of emergency pre-warning messages is of significant value to enable the target audience to prepare in advance and mitigate disaster losses. To investigate the impact of information expression on the reach of emergency pre-warning messages, this study, based on prospect theory and reference point effect, employed an experimental research method to collect self-reported perception and behavioral data from the audience of pre-warning messages in the context of urban rainstorm disaster. The influences of the information expressions including different reference points on the effectiveness of information arrival were examined. The results indicated that information expression designed based on different reference points has different effects on the reach of disaster pre-warning messages. Specific information reference points and social comparison reference points significantly affect the audience's perception of disaster severity and risk, while the negative impact reference point does not have a significant effect. Furthermore, cognitive load affects the reach of information that contains both comprehensive reference points and specific information reference points related to disaster prevention measures. This study advances the research on information reach theory and has significant implications for improving government information expression, enhancing the effectiveness of disaster pre-warning messages delivery.

Key words: Language expression, Information reach, Disaster warning, Reference point, Emergency management