The Korneti – Peļļi ravines were created by the melted waters of glaciers at the final stage of the last ice age approximately 12 thousand years ago. The powerful streams of water have made one of the most spectacular reljefs in Latvia – the “Korneti – Peļļi” ravines.
The total lenght of the Korneti – Peļļi ravines is about 25 km, and they are located both in Latvija and Estonia. When the oce of the glaciers had melted completely 15 lakes formed in the lowest places of the deep ravines. The lakes are narrow and deep with steep shores.
The deepest lake of the ravines and also the deepest lake lake in the Alūskne region is lake Raipals (the deepest place – 35 m). The smallest of the lakes is Lake Trumulītis which is also the source of the river Pērļupīte.
Five of the lakes are located on the Latvia-Estonia border – Lake Peļļu, Lake Smilšājs, Lake Sūneklis, Lake Ilgājs and Lake Mazais Baltiņš that is the second deepest lake (the depth – 32 m) in Estonia.