In the autumn of 1969, a catastrophic advance of the Kolka Glacier was detected in the Genaldon River basin near the city of Ordzhonikidze. This attracted the attention of specialists in various fields, particularly glaciologists. The already tense situation was aggravated by local residents’ fragmentary recollections of the enormous “Genaldon catastrophe” of 1902. A special commission dispatched to the area in October 1969 confirmed that the Kolka Glacier had advanced considerably, reaching the Maili Glacier. Its activity then declined sharply toward the end of October. No dangerous accumulation of water was discovered within the glacier basin, and it was therefore concluded that the sudden advance had ended and that the threat of destruction in the area had disappeared. At the beginning of November, however, the glacier resumed its powerful advance, which continued until early January 1970. Despite the extremely gentle gradient of the valley, the glacier front sometimes advanced at a rate of several tens of meters per day, while the advancing glacier tongue reached a thickness of 130 meters. Between early November and early January, the glacier moved two kilometers down the valley, burying the exceptionally valuable mineral springs of Upper Karmadon and creating a genuine threat of subsequent outburst floods, flooding, and eruptions of water and ice. It was evident that the advance of the Kolka Glacier was not an accidental event comparable to the “collapses” known from the literature, but rather the result of a complex interaction among numerous natural processes in the glacial zone, most of which remained unknown. The task, therefore, was to conduct a rigorous glaciological investigation of this rapid glacier surge in order to develop a sound and practicable program of monitoring, forecasting, and protective measures. It was also necessary to determine the true causes, regularities, and possible scale of such phenomena, which are of great importance for the development of mountain regions. At the beginning of 1970, the Institute of Geography of the Academy of Sciences of the USSR joined the investigation. A special expedition was established within the institute’s Department of Glaciology. In addition to conducting field investigations in the Genaldon glacial basin, the expedition was also responsible for early-warning monitoring and information services. Although the Institute of Geography of the Academy of Sciences of the USSR had previous experience in studying similar glacier advances, particularly the surge of the Medvezhiy Glacier in the Pamirs in 1963, the members of the expedition were in fact working on a scientific problem that had never been comprehensively investigated and therefore required a broad, integrated approach. The work formed part of the international glacier-fluctuation observation program, particularly its most important component, which sought to clarify the physical causes and mechanisms of sudden glacier surges and ultimately to establish a foundation for forecasting them. The expedition’s research program was developed by A. N. Krenke, K. P. Rototayev, and V. G. Khodakov under the supervision of V. M. Kotlyakov, Corresponding Member of the Academy of Sciences of the USSR. The field investigations were directed in practice by K. P. Rototayev, head of the expedition. The expedition conducted meteorological observations within the basin and analyzed the conditions governing the formation of the heat, mass, and water balances in the glacial zone, as well as the conditions sustaining modern glaciation in the Genaldon basin. Geodetic surveys and cartographic work were carried out, establishing a basis for quantitatively assessing the structure of the basin, its glaciation, and the various parameters of the Kolka Glacier. A series of maps documenting conditions during specific periods was also compiled. Hydrological observations were undertaken to clarify the conditions governing the formation, accumulation, and structure of runoff from glacial meltwater and atmospheric precipitation, and to predict the possibility of dangerous outburst floods and mudflows. Geological-geomorphological and engineering-glaciological investigations of the glacial zone were conducted using geophysical methods. These studies made it possible to determine the origins and parameters of most Quaternary landforms and deposits in the area, and to establish the scale and relative chronology of several major glacial changes and catastrophes. Direct glaciological investigations included detailed studies of the structural characteristics, mass balance, and dynamic evolution of the Kolka Glacier; the conditions governing the formation and development of its surge; and the origins and nature of the secondary glacial processes triggered by its advance. All these investigations were supplemented by the interpretation of aerial photographs taken in different years, visual observations from aircraft, and the collection, organization, and study of historical materials, eyewitness accounts, and scattered published data concerning the Genaldon glaciers and their basin, together with other necessary research. Analysis of these materials made it possible to reconstruct with considerable clarity the state of glaciation in the past and the nature of the 1902 “Genaldon catastrophe.” The study of that event was highly important for understanding both the present condition of the glaciers and their possible future changes. In addition to field observations, a number of important calculations were performed. The possible volume of water accumulation within the Kolka Glacier basin and the potential volume of outburst floods were estimated. These calculations made it possible to assess realistically the degree of threat to the local population and economy and to develop an effective system of emergency measures against natural disasters. 段落 10 Field investigations frequently had to be conducted in inaccessible and hazardous high-mountain areas. A large number of personnel participated in the expedition’s work over the course of eight years. Although it is impossible to list here every participant in these long-term investigations or to single out any individual, the authors express their respect and gratitude to all of them for their selfless and arduous work, without which the practical advancement of modern glaciological science would have been impossible. The book is structured so that its successive chapters present, first, the preliminary results of the initial reconnaissance work; second, a synthesis of the first research cycle and the resulting forecasts of fundamental glacial processes; and finally, revisions to the conclusions thus obtained on the basis of subsequent years of investigation. The monograph is based primarily on research materials collected between 1970 and 1975, with partial use also being made of results obtained during 1976–1978.