Space-Based Observation of a High-Altitude Red-Coloured Glacial Lake in Ladakh, Northwest Himalaya, India

The present study reports the existence of a unique and unusual feature of the Zanskar valley, Ladakh, India – a proglacial ‘red/brown-coloured lake’ observed from space-based remote sensing data. The lake has not changed in colour and size over the years. Here we report observations from 2004 onwards till recently. The local geology plays an important role, and iron-dominated lithology of the region interacts with snow and glacial meltwaters and subsequently deposits red/brown-coloured suspended silt in this proglacial lake. Spectral analysis of reflectance data from Sentinel-2 images in visible–infrared region of electromagnetic spectrum suggests that the colour of the lake is due to high concentration of suspended solids, having dominant reflectance at 660–700 nm and thus causing the red/brown colour of the water.