Traumatic incidents, when they occur suddenly and unexpectedly, are out of the ordinary and there is a perceived lack of control over them, such as human-made or natural disasters, can be divided into three different phases. Each phase differentiates in the knowledge, skills and group interventions required:
1. the Impact phase: the immediate period after disaster strikes
2. the Immediate ‘Post-Disaster’ phase: recoil and rescue: any time from the day after the onset of the disaster until approximately the eighth to twelfth week
3. the Recovery phase: generally beginning at about the eighth to twelfth week after the onset of the disaster