What: Irregular or half-moon shaped moraine formations
How: Ribbed moraines formed beneath the inland ice when type of soil called till accumulated in layers bit by bit. In terms of size, Ribbed moraines are considerably larger than De Geer moraines.
Where to see: In the Kvarken Archipelago you can explore Ribbed moraines on the mainland at Köklot or at the outer islands of Valsörarna and Mickelsörarna.
Fun fact: Sometimes Ribbed moraines look a bit like waves from above.