Disasters can happen at any time and it's not if it will happen but when. Disasters also have a life cycle and realizing this emergency management matches the disaster life cycle with a series of phases that include strategies to mitigate the hazards, prepare for and respond to emergencies and to finally recover from their effects. These four phases are not independent, but instead are integrated with each other phase in a continual evolution. The four phases are comprised of various functions and activities, some of which are independent, while others are dependent upon other functions.
- Mitigation refers to activities which actually eliminate or reduce the chance of occurrence or the effects of a disaster. Examples include reinforcement of a roof to reduce structural damage from high winds, preventing use of hazardous areas such as flood plains, or adjusting the use of such areas by elevating structures to reduce the chance of flooded houses.
- Preparation is planning how to respond in case an emergency or disaster occurs, and working to increase resources available to respond effectively to the disaster. Preparation activities are designed to help save lives and to reduce property damage by preparing people to respond appropriately when an emergency is imminent. The development of the city emergency operations plan is a preparation activity, such as assembling an individual disaster kit.
- Response activities occur during and immediately following a disaster. They are designed to provide emergency assistance to victims of the event and reduce the likelihood of secondary damage. Police, fire and rescue services are the primary responders during the response phase.
- Recovery is the final phase of the emergency management cycle. Recovery continues until all systems return to normal, or near normal. Short-term recovery returns vital life support systems to minimum operating standards. Long-term recovery from a disaster may go on for years until the entire disaster area is completely redeveloped, either as it was in the past or for entirely new purposes that are less disaster-prone.Relocation of portions of a flood-prone town and turning the area into an open space or parkland is a recovery example. Recovery planning should include a review of ways to avoid future emergencies.