A long brooding pool with a depth of about 12 ft, Floutern Tarn drains east and then north into the morass of Mosedale. A walker's pass, Floutern Tarn Pass, crosses beside Floutern, providing access from Buttermere to Ennerdale. The western side follows Gill Beck, the southern boundary of Gavel Fell.
A deep lake with a depth of about 12 ft, Floutern Tarn is drained by streams flowing east and north into Mosedale's wetland area. A passage for pedestrians, Floutern Tarn Pass, lies adjacent to Floutern, providing access from Buttermere to Ennerdale via a walking route. The western edge follows Gill Beck, which marks the southern boundary of Gavel Fell.