According to the website Journey to Firefighter there are four stages to a fire:
The first stage is a very small fire, known as the ignition (or incipient point) which may go out on its own. In the case of the Cocoanut Grove, this would be mostly closely represented by the instant when the first palm tree caught fire.
The next stage of any fire, called the growth stage, is when the fire finds additional fuel in the form of structures and oxygen. This is the time when a deadly flashover can occur. In the Cocoanut Grove fire, the ignition of the entire faux ceiling would represent this stage.
When the fire reaches its third stage it is considered fully developed. This is the hottest and most dangerous stage of any fire. Once the fire in the Cocoanut Grove had spread to the main floor and then throughout the different lounges it was fully developed.
The final stage of a fire, called decay, is when the consumption of all possible fuel and oxygen causes the fire to die. By the time this stage was reached through the work of firemen on the scene, the Cocoanut Grove was destroyed and 495 people had died.