Acting as the Incident Commander you have completed a size-up to include identifying hazards and safety issues, setting priorities, determining resources, and defining key initial incident management locations.

Now that you understand what you are trying to accomplish and what resources you will be managing, you will need to define the ICS structure that will be needed to support management of the incident.

At this point in the scenario, the Incident Command likely consists of the Fire Chief working over the hood of a command vehicle. Additional resources will be arriving soon and the Incident Commander will need additional staff personnel to help in the management in the incident response.

There are several NIMS Management Characteristics that can be applied to determining the appropriate ICS structure for an incident:

• Chain of Command and Unity of Command: All resources should work for a single general staff section and all general staff sections should report to and receive direction from a single IC.
• Manageable Span of Control: the ICS structure must be of a sufficient size to assist the IC in effectively managing the incident. A key to this is constraining the number of subordinates or functions that each supervisor manages.
• Modular Organization: what pieces of the ICS structure are needed to manage the incident? Think ahead to the next operational period because what you need then often must be asked for now.