The Himalayan range includes about 15,000 glaciers, which store about 12,000 km3 (3000 cubic miles) of freshwater. The Himalayan mountains are located in the northeastern part of India and pass through several countries including Pakistan, China, Afghanistan, Nepal and Bhutan. The glaciers in the Himalayan mountains are at the headwaters of many essential and large rivers throughout the Himalayan and Asian countries. Over the last 30 years some glaciers in the Himalayas have retreated one kilometre. The negative effects of climate on the glaciers have caused the glaciers to melt, or retreat having a lot of drastic effects. Over time, as a result of glacier shrinkage, normal glacier melt will not be able to contribute to the Himalayan region's water supply each year. Water availability will not be affected at low elevations as they are mostly dependent on monsoon rains, however at higher elevations glacier retreats will result in streamflow alterations in some basins. .
GLOF or Glacial Lake Outburst flood is when lakes, formed by the melting of glaciers overflow causing floods. This a very serious issue in the Himalayas as these lakes are near large rivers which are densely populated with villages and farms. Tsho Rolpa glacial lake is located in Dolakha district of Nepal and is one of the biggest glacial lakes in the Himalayas, has been categorised by scientists as the most potentially dangerous glacial lake in the country. Tsho Rolpa was made by the melting of several glaciers in the valleys above it. If the lake was to burst through its unstable dam, it would destroy the lives and livestock of over 6000 villagers living around the Tamakoshi River. Tsho Rolpa has had a high-tech early warning system to alert the communities about the Glacier Lake Outburst Floods (GLOF). The advanced technology will alert people downstream if the level of water increases in the lake and also keep on communicating the locals about the status of lake and the daily weather systems.