The present study aims to analyse the effect of the passage of time on the phenomenological characteristics of the memory of a traumatic event of social relevance. The terrorist attack that took place in Barcelona (Spain) in August 2017 was taken as the traumatic event. A priori, this event meets the criteria to produce a flashbulb memory (level of surprise, consequentiality and emotional activation). A total of 364 memories from different individuals (78% women and a mean age of 20 years) were studied at five different time points, between September 2017 and December 2018, using the CCFRA/PQAM questionnaire. The results show that the memories only comply with the characteristics usually associated with flashbulb memories in the medium term (about 7 months after the events). These characteristics do not appear in a clear way immediately and are lost just over a year after the event. Therefore, the passage of time seems to have a great influence on the characteristics of memories of violent events, such as terrorist attacks. However, this influence may depend more on the relevance given to the event than on the elapsed time, as it is the relevance that determines the number of subsequent recalls, influencing the maintenance of the memory.