The Ash Wednesday bushfires were one of the worst natural disasters in Australia's history. This paper documents observations of human reactions to the disaster started immediately after the bushfires. Two frameworks were used for classification of observations: biopsychosocial and temporal. Biological, psychological and social reactions in adults and children are described as they occurred before, during, immediately after, and two months after the disaster. Some reactions in animals are noted. Victims of the bushfires were seen to have reacted during the various phases of the experience in a predictable way: during the acute danger, when survival was paramount, and immediately afterward, the usual patterns of hierarchical structure within families and in the wider community broke down and new social structures emerged. These reverted to previously existing patterns in the ensuing months. Feelings of disorientation, unreality and anger at outside agencies, which were viewed as hostile and unhelpful, were commonplace. The findings have implications for the development of everyday stress reactions and clinical syndromes presenting to clinical practitioners. Lastly, the role of intervention for disaster reactions is examined and its usefulness noted.