From the hydrographic phenomena in the National Park “Pelister” the glacial lakes are especially important. Vasilevski (2005) records and gives detailed data for 8 mountain lakes, of which 3 permanent, 3 periodic and 2 occasional. According to the same author, depending on the factors that led until the creation of their pools, these lakes can be divided into: erosive, accumulative and combined. The group of permanent lakes includes the Big and Small Pelister Lake and Dimitrov Lake.
Periodic lakes include: Lake Eagle, Lake 8 and Lake Hospitals. These lakes have water in their lake pools only during the wet period of the year, while during the dry season their pools are completely dry and waterless. Occasional lakes include the two smaller lakes located south of Lake Bolnici, or south of the Great Pelister Lake. These lakes have water only in their pools during intense snowmelt and snowfall during the spring and during the onset of intensive rainfall.