Lasafam Iturrizaga

Trends in 20th century and recent glacier fluctuations in the Karakoram Mountains

The article provides an overview on the trends of 20th century and recent glacier fluctuations since the end of the 19th century in the Karakoram Mountains. Recent glacier variations in the subtropical mountain range of the Karakoram Mountains were surveyed on the base of field observations carried out in the period of 1992–2006 on 57 glaciers. Historical documents, such as photographs and travel reports, as well as air and satellite images have been included in the compilation. The occurrence of ice-dammed lakes, which have mainly been formed by advances of tributary glaciers into the trunk valleys, has been used as further indicators for glacier fluctuations. Even though a considerable part of the Karakoram glaciers have shown signs of glacier retreat, most of the longer glaciers (> 45 km), such as the Baltoro and Batura glaciers, have been rather stationary in the last century. Even some of the clean glaciers, such as the Yazghil and Barpu glaciers, did not retreat significantly. Singular glacier advances and surges occurred over the entire study period, whereas the average distance of the surges has apparently become smaller over time. The glacier behaviour of the avalanche-fed glacier is highly dynamic. Geomorphological indicators, as localised glacier thickening resulting in overtopping and breakthroughs of lateral moraines, the new moraine formation and the shape of the glacier tongue has to be handled carefully for drawing conclusions on the entire mass balance of a glacier. In the whole, the dynamics of the Karakoram glaciers proves to be different from the neighbouring mountain ranges, such as the Himalayas and Tienshan, which are characterized by a dominant glacier retreat. The reasons lie in the different topographical and climatic settings. Topography is apart from the complex climatic situation one of the major controlling factors governing the individual glacier fluctuations in the Karakoram Mountains.

Glacier-Induced Hazards as a Consequence of Glacigenic Mountain Landscapes, in Particular Glacier- and Moraine-Dammed Lake Outbursts and Holocene Debris Production

With the help of representative examples this paper attempts to infer the damaging effects, induced by glaciers, not only — as is normally the case (cf. amongst others, Hewitt 1982, 1988, 1995) — from the geomorphodynamics, observed directly on the spot, but from the entire glacigenic character of the high mountain landscape. Accordingly, not only the current changes of the glacier, which produce damage — as for instance the shifting of the glacier termination (cf. 3.) — are on the focus of interest, but also the development of the glacigenic relief during the High- to Late Glacial (cf. 2.). From the mountain shaping through prehistorical glaciation, partly filling up the relief, a transformation of the valleys resulted, which was not stable during the Interglacials. Characteristics of the glacial relief, such as U-shaped valleys, subsequently crumbled away on their typically over-steepened valley flanks and collapsed as soon as, following deglaciation, the abutment of the ice filling was absent in the valley. This is a process which, in the Interglacials, the preglacial U-shaped valley relief — depending on the length of time passed since deglaciation and according to resistance of the valley flanks — more or less quickly reestablishes. Through the processes proceeding as a result, i.e. wet and dry mass self-movements such as rockfall, rock slide, landslide etc., debris bodies are built up on the valley floors. These directly or indirectly result in or induce in the form of fans, cones and screes numerous damaging effects (cf. 4.).

In Memoriam: Matthias Kuhle

Matthias Kuhle, an internationally renowned physical geographer and highly respected geomorphologist, died tragically on the 25th of April, 2015. He was in the Manaslu Himalaya, close to the epicentre of April 2015 Nepal earthquake at Magnitude 7.8, and was fatally injured.

The valley of Shimshal – a geographical portrait of a remote high mountain settlement and its pastures with reference to environmental habitat conditions in the North-West Karakorum (Pakistan)

This article presents observations on the natural hazard potential for permanent and seasonal mountain settlements and infrastructure such as routeways and irrigation canals in the North-West Karakorum. The remote high mountain settlement Shimshal (3080 m), located in the upper Shimshal valley and surrounded by three potential natural glacier dams, is of particular interest. The permanent settlement of Shimshal and its seasonal pasture settlements in the Shimshal Pamir at heights of 3200 and 4600 m respectively, reach the upper limits for permanent and temporary settlement. The choice of location for settlement and agricultural activities is already dictated by relief conditions. Primary settlement areas are the sediment accumulations in the valley floors. The wide distribution of unconsolidated screes in particular prevents settlement expansion upwards along the valley slopes. Glacial outburst floods as well as seasonal flooding events further reduce the scanty settlement area, as well as being among the most devastating sources of danger. The production of debris and the supply of loose material deposits induced in connection with the glaciation history of the area becomes a permanent source of danger for human settlement through resedimentation in the form of rockfall or mudflow. Furthermore, canal systems essential for the survival of oasis settlements suffer annual destruction through mass movements on the slopes, induced by the glacially pre-formed relief. Thus the adaptation of settlement locations to a glacially formed mountain relief will be examined in this study, with particular reference to the geomorphological landscape situation. What makes the Shimshal settlement particularly interesting is its very isolated location at a distance of 80 km from the Hunza valley which contains the main settlement concentration of the North-West Karakorum. Traditional ways of life can be expected to be well protected from outside influences. In the North-West Karakorum we find a debris landscape which differs greatly in its development and distribution from that of the Himalayas, influenced particularly in the lower valley locations between 1000 and 3000 m by the different climatic situation, and where therefore in comparison with the Himalayas a completely different pattern of natural hazards arises.