Abstract
Whereas certain crisis situations seem to favor the emergence of improvised modes of action, other situations highlight the actors' inability to improvise. A case study of crisis where 4 groups of actors were involved is presented. Even though the situation under study presents a combination of conditions that were likely to both favor and hinder improvisation, the observations of the case suggest a lack of improvisation in the management of the crisis. The analysis leads to suggestions that: 1. The emergency of improvisation depends on critical thresholds beyond which certain conditions favoring improvisation become conditions hindering improvisation. 2. The involvement of several groups with strong professional identities leads the actors to rely on their identities and to repeat the roles they have learned. 3. The combination of an absence of interaction among the group, and of maintenance of strong intra-group modes of interactions, hinders the process of collective sensemaking that is necessary to improvise