Data are presented from hydrological observations from the englacial stream of the Bertil Glacier and from the terminal section of the glacier. Two types of englacial runoff regime during the ablation season have been identified. During the course of the first type of runoff, a rapid type, observed in the 1960s and 1970s, the volume of intraglacial discharge comprised 40% of total discharge. The second, slow type, whereby the volume of intraglacial discharge comprises only 10–20% of the total, dominated in the 1980s. Complete freezing of the central intraglacial discharge tunnel was recorded by the end of the cold period. Water entering the glacier in the spring of 1984 and 1985 produced a high head of pressure and resulted in the occurrence of geysers on the lower part of the glacier surface. It is assumed that the changed nature of intraglacial discharge is associated with the progressive freezing of the glacier and with changes in its hydrothermal regime. If climatic conditions remain the same, over the next 30–40 years compound discharge, i.e., involving both supraglacial and intraglacial runoff, will possibly give way to supraglacial runoff. This will affect the landforms in the terminal area of the glacier and exclude any possibility of it being used as winter water supply for the Soviet settlement at Pyramiden.