The emer­gence of a whirlpool is asso­ci­at­ed with the inter­ac­tion of tidal waves with a com­plex bot­tom topog­ra­phy and a high­ly indent­ed coast­line. It is a sys­tem of eddies in the strait. Moskstrau­men is actu­al­ly one of the old­est mael­stroms found in the open sea. There are sev­er­al whirlpools around it mak­ing it very dan­ger­ous.