Photogrammetric analysis of a slush torrent in the Karkevagge, northern Sweden

Slushflows have been investigated in various regions of the Earth for more than forty years. Most of the observed events occurred in mountainous drain age basins at high latitudes, so relatively few observations and measuremen ts are presented in the scientific literature. This particularly holds for slush torrents which are major slushflow events reaching supercritical flow velocities. Thus, information on dynamical features of slush torrents are rather limited, and most results are based on qualitative observations. On June 3, 1995, during a field campaign in the Karkevagge, a drainage basi n in Swedish Lapland, a slush torrent could be observed and documented by a time series of photographs and by video recordings. Quantitative results f rom a photogrammetric analysis of the photographs show that the first wave front of that slush torrent reached peak velocities of more than 40 ms(-1). A second wave front was able to reach even higher velocities due to the fa ct that the first wave had almost completely removed all snow from the tran sport path. Consequently, the viscosity of the flow was significantly reduc ed. To the author's best knowledge, these results are the first quantitativ e measurements of a slush torrent during its movement.