Emergency managers receive communication training about the importance of being 'first, right and credible', which is not easy. For instance, in October 2018, the Aude department in the SouthWest of France was hit by intense rain. Flash floods were hard to forecast and only the 'orange' level of vigilance could be raised initially, but the population dismissed this very usual warning in that season. The 'red' level was then raised too late, leading to high criticism. The main problem here is the loss of trust induced by too many 'false alarms'. In this paper we propose a serious game called VigiFlood for raising awareness in the population about the difficulty of crisis communication and their own responsibility for reacting to the alerts. The implemented game still has limited functionality but already shows interesting results in helping the user to visualise and understand the trust dynamics.