Korouoma is about 30 kilometers long valley, the mountains surrounding are apart of hundreds of millions of years old bedrock. You can go hiking, skiing or snowshoeing through the entire 30 km long gorge or staying on the 5 km long Koronjää trail.
The falling small streams that descend from the cliffs will freeze into a solid ice during the winter. Rainfall and frost affect the number and shape of ice dust. For most hikers, it is enough to miss the falls, as active climbing enthusiasts defy the frosts and climb up the rocks towards the rock floor.
http://posiolapland.com/korouoma