The Netherlands has a new tool to alarm and inform the population in case of crises. NL-Alert can simultaneously draw people’s attention and explain the crisis matter. The use requires determining of both the impact area and the alarm text. This raises questions about required knowledge and expertise to compose messages. Current experiences are mainly based on communication aimed at educating about potential future crisis. Composing a textual message in limited time to alarm the population is a different job. A good message meets three criteria: completeness (description of threat, location and action), relevance (receiver can determine if alarm is intended for him/her) and correctness given situation. TU Delft analysed messages composed by experts and laypeople on length, content, structure and readability. Results show anyone can compose an alarm message, the difficulty lie in decision on deployment and being able to gather information for the correct and relevant message content.