The purpose of this paper is to explore how a number of processes joined to create the microlevel strategies and procedures that resulted in the most lethal and tragic forest fire in Portugal’s history. The paper shows how structure collapse led teams to use only local information prompting acts of improvisational myopia, in the particular shape of corrosive myopia, and how a form of incidental improvisation led to catastrophic results. The research offers insights into the dangers of improvisation arising from corrosive myopia, identifying ways to minimize them with the development of improvisation practices that allow for the creation of new patterns of action.