Factors of formation and development of supraglacial lakes and their quantification

Anotace: Supraglacial lakes greatly affect the rate of glacier ablation and a potentially dangerous (GLOF – Glacier lake outburst flood) proglacial lake often forms through their development. The main part of the paper recapitulates the factors of the formation and drainage of supraglacial lakes, as well as the mechanisms of their development through a review of the scientific literature. In total there are five factors of the formation of supraglacial lakes and four factors (three of them alternative to one another) of the drainage. Three factors delimit the maximum extent of the emergence of supraglacial lakes, two of them determine the detailed distribution of localities suitable for hosting supraglacial lakes. The circumstances leading to the drainage mainly reflect the decisive role played by englacial voids. According to the current degree of scientific knowledge there are no factors controlling the development of supraglacial lakes. The complete process of the expansion of a supraglacial lake may be viewed as a positive feedback loop consisting of three major mechanisms. In the final part all of the factors are provided with quantitative intervals responding to the respective probability scales, which enable a relatively objective assessment of the probabilities of formation/drainage of supraglacial lakes. The most frequent application is the case of the assessment of the probability of the formation of a large supraglacial lake, due to its likely development into a proglacial lake.