Bhutan is blessed with enormous fresh water resources and at the same instance challenged with constant threat from natural disasters. The fresh water resources such as the high altitude lakes, glacial lakes and glaciers are scattered on the northern end of the country that feeds into the river system. However, the fragile northern glacial lakes and retreating glaciers are like time bombs that can cause a devastating effect when changing climates and global warming could increase the rate of glacial retreats and cause devastating floods downstream. Such an incident was recorded in October 7, 1994 where the Punatsang Chhu watershed was flooded and the nation experienced a real time flood event killing dozens of people on its path and destroyed the ancient capital of Bhutan.
This remote sensing project expands on previous work where two annual Landsat images (Oct 30, 1999 and Oct 1, 2009) that were a decade apart were analyzed to see if there were regional glacial melts. The results from the three methods – Maximum Likelihood Supervised Classification, Thresholding of TM4/TM5 Ratio and Thresholding of Normalised Difference Snow Index – indicates that glacier (snow and ice) is melting in Lunana, Bhutan – the highest mountain relieves found on Earth.