"Every year, millions of people are affected by both human-caused and natural disasters. Disasters may be explosions, earthquakes, floods, hurricanes, tornados, or fires. In a disaster, you face the danger of death or physical injury. You may also lose your home, possessions, and community. Such stressors place you at risk for emotional and physical health problems. Stress reactions after a disaster look very much like the common reactions seen after any type of trauma. Disasters can cause a full range of mental and physical reactions. You may also react to problems that occur after the event, as well as to triggers or reminders of the trauma."
Department of Veterans Affairs: http://www.va.gov