Korouoma is about 30 kilometres long, few hundred meters wide and up to 130 m deep canyon at Posio, Finland. The entire area is a natural reserve. At the bottom of the canyon there's Korojoki River, which ends up to Kemijoki River. Part of Korouoma's distinctive nature are the clifs both sides of it, where several streams freeze during the winter forming huge ice formations. Because of these ice formations Korouoma is known as the best ice climbing location in Finland. There are some climbing routes that can be used during the summer time as well.