Systematic observations of Himalayan glaciers over the last few decades provide reliable indications of continuous shrinkage of most of the glaciers. Changes in mass, volume, area and length of glaciers are reported, but an up-to-date regional assessment of glacier changes is lacking. In the present study, satellite data, maps and ground-based measurements have been used to obtain the snout retreat and surface changes of the Tipra Glacier in the Alaknanda river basin of the Garhwal Himalaya for the period 1962–2008. The study reveals that a large part of the glacier has been detached from the main trunk and separated into the Tipra (7.5 km2) and Rataban (7.4 km2) Glaciers as it had one outlet (snout) in 1987. Between 1962 and 2002 estimated surface area reduced by ~18% and snout retreat was ~535 m with an average rate of 13.4 m a−1. Measurement of snout positions of the Tipra and Rataban Glaciers from 2002 to 2008 indicates an enhanced annual retreat of 21.3 and 21.2 m a−1, respectively. Total frontal area vacated during this period was calculated to be 0.084 km2 for Tipra Glacier and 0.028 km2 for Rataban Glacier. The estimated Equilibrium Line Altitude (ELA) rise was 76 m for the Tipra Glacier and 57 m for the Rataban Glacier. Accumulation Area Ratio (AAR) was calculated as 0.47 for the Tipra Glacier and 0.49 for the Rataban Glacier, during the study period. The observations compared with the other studies carried out in the region show a significant reduction in glacier areas. The increased retreat rate of glacier snouts is probably a direct consequence of global warming. The present snouts of the Tipra and Rataban Glaciers are located at altitudes of 3865 and 4120 m, respectively.

During the extreme precipitation event of 15th-17th June 2013 in Garhwal Himalaya, glacial lake outburst flooding accompanied by numerous landslides and flash flood events caused widespread death and destruction. Many hill slopes and steep river banks had developed fractures and fissures indicative of landslides and one such scarp was observed at Kunjethi (Kalimath) village on satellite images during routine analysis. Rainfall threshold analysis for years 2012, 2013, 2014 and 2015 has confirmed that it was the main triggering factor which happened due to extreme precipitation in June 2013 leading to scarp development and initiation of landslide. In order to characterize the landslide and get subsurface information, two highly cost-effective and fast non-invasive geophysical techniques, electrical resistivity tomography (ERT) and ground penetrating radar (GPR), were used. Four ERT profiles and one GPR radargram profile were used to determine the approximate depth to slip surface, which is inferred around 15-19 m. Integration of satellite remote sensing, geophysical studies and field observations have been used to demarcate the maximum possible slide zone. This study reiterates that earth observation tools in integration with faster, non-invasive and cost-effective geophysical techniques can establish the slip surface, which is an essential information required for landslide hazard mitigation measures.

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