ИСТИНА

Lovozerskiye Tundry is a plateau-like mountainous massif located in the central part of Kola Peninsula 10 km eastward from the Khibiny Mountains. Slushflows – one of the main processes of valley development there – are a specific subtype of debris flow. Geomorphic interpretation of high-resolution satellite imagery from public services and topographic maps displayed widespread distribution of geomorphic evidences of debris flow phenomena within the massif. Detailed field survey conducted in 2017 generally confirmed these results. Particular landforms and deposits specific for active slushflow origination, transit and deposition zones were observed in 23 out of 30 investigated valleys longer than 3 km. Apparently, at the Lovozerskiye Tundry most of slushflows initiates in narrow deep channels at the larger basins upper reaches by rapid snowmelt, possibly added by rainfall. In addition, gravitational slushflows usually localize in steep avalanche tracks starting as wet snow slab failures similar to wet snow avalanches. Typical granular debris flows – with low content of fine material – are possible, at least, in four basins due to periodical extreme water discharges triggered by avalanches and/or rockfalls into moraine-dammed lakes in their headwaters. It was also established that granular debris flows in the lower valley reaches could start as slushflows in their upper parts. Thus, during the 2017 field campaign initial stages and consequences of such a complex event were observed on July 3 in the Sengisjok valley. The following field survey has established the limits of all morphodynamic zones and maximum splash levels of the event.