During major disasters, at what point in the decisional process do senior government officials transition from developing necessary situational awareness to perform decision making? This "transition to decision making" (TDM) concept was analyzed through a structured interview survey of 25 current and former US Federal Coordinating Officers (FCOs) and focused on their decision-making process during the initial response period in a Presidentially declared Stafford Act disaster. This analysis suggests that the TDM for these emergency leaders is influenced by the following five factors: 1) Analogue Factor: the decision maker's previous knowledge and experience from analogous disaster situations; 2) New Paradigm Factor: the degree to which the disaster situation is very atypical to the decision maker due to hazard type and or situation severity, 3) Data Capture Factor: the quality, amount, and speed of disaster situation data conveyed to the decision maker; 4) Data Integration Factor: the decision maker's ability to integrate situational data elements into a mental framework picture; and 5) Time Urgency Factor: the decision maker's perception as to time available before a decision has to be made. The article describes the factors and graphs that how these may influence the timing of the TDM in four types of emergency situations faced by FCOs: 1) an analogue disaster, 2) a disaster situation that presents a new paradigm, 3) an intuitive disaster situation, and 4) a disaster requiring an urgent response.