The posttraumatic sequelae for 104 adult inhabitants from the town of Flateyri. Iceland, were studied 10 weeks after an avalanche hit the town killing 20 people. Eighty-seven adults from the neighboring town of Thingeyri constituted a control group. On the basis of the General Health Questionnaire (GHQ-30), 25% of the Flateyri group (twice as many than in Thingeyri) reached a level of psychiatric caseness. The most common symptoms were intrusive thoughts and feelings, tension, sadness, and anxiety. The loss of family members was associated with symptomatology. A high number of former life events correlated more strongly with distress symptoms than with the individual appraisal of these events. Distress symptoms were related to gender, age, and education.