The head of the Wasdale Valley is surrounded by some of the highest mountains in England, including Scafell Pike, Great Gable and Lingmell. The steep slopes on the southeastern side of the lake, leading up to the summits of Whin Rigg and Illgill Head, are known as the Wastwater Screes or on some maps as The Screes. These screes formed as a result of ice and weathering erosion on the rocks of the Borrowdale Volcanic Group, that form the fells to the east of the lake, towards Eskdale. They are approximately , from top to base, the base being about below the surface of the lake.