Abstract:
The article presents the newest results of field observations of rock glaciers in Rila and Pirin mountains, made in the autumn of 2015 and the summers of 2016 and 2017. Rock glaciers can be considered a typical landform in the high mountain areas of Rila and Pirin. More than 70 rock glaciers exist in the mountains of Bulgaria, at altitudes between 2200 and 2700 m a. s. l. Most of them are considered relict, formed in conditions colder than the present climate and warmer (or drier) than the climate during ice ages. However, it may appear that some of the highest rock glaciers are rather dormant than relict, or even active. A large number of rock glaciers was described and observed in the last two years, and some measurements were done. Thermistors for continuous measurement of ground temperature were installed in several locations to evaluate ground thermal conditions throughout the year, and respectively the possibility of the occurrence of permafrost and present-day activity. 782 Schmidt hammer tests were done on rock glaciers in Rila and glacial landforms in Rila, results indicate younger age in upper sections.