A Norwegian multicentre study of the winter 1985-1986, when 328 injured skiers were compared with a control population of 316 uninjured skiers, revealed a significantly lower injury risk for skiers on ungroomed than for skiers on groomed slopes. Thirty-seven skiers were injured on ungroomed slopes, and skiers aged 15-29 years were at risk. The population of uninjured powder skiers was significantly younger than the uninjured skiers on groomed slopes. Beginners were significantly overrepresented among the injured powder skiers, but the skiing ability for uninjured powder skiers was significantly higher than for uninjured skiers on groomed slopes. In conclusion, a lower injury risk was recorded for powder skiers than for skiers on groomed slopes, probably due to a higher skiing ability of the powder skiers.