The coordination of out-of-scale events requires that teams form and work together quickly and effectively.  At the incident management team level and above, teams managing out-of-scale events will likely include people who do not know each other, may have very different skill sets and knowledge, and may be from different agencies that have different priorities and perspectives on the incident. As an incident scales up new members of the team are added, increasing the functional unit and coordination complexity. Also as incidents continue in duration, shift replacements become necessary to manage fatigue.  This paper investigates the way that these issues have led to breakdowns in coordination through semi-structured interviews with people who have recent experience of out-of-scale events in Australia and New Zealand.  Fourteen semi-structured interviews were conducted with people who have a role in emergency management at the incident management team and above.  Key issues that emerged from these interviews were: understanding the skills and abilities of team members; taking over control from another team, the use of informal networks, and conflict between different agencies. These issues could lead to individuals and teams not possessing important information, resulting in degraded team performance and an impaired operational response.   In out-of-scale events, people can become overwhelmed and tasks that would normally be carried out are dropped as people try to cope with the high levels of stress and workload.  The findings from this research demonstrate the need to consider team processes and to ensure effective information flow even under the extreme pressures of an out-of-scale response so as to avoid breakdowns in coordination and a degraded operational response.