The fundamental objective of this collaborative study is to develop a thorough and systematic assessment of the contribution of both seasonal snow and glaciers to the water resources originating across the Himalaya, Karakoram, Hindu Kush, Pamir and Tien Shan mountain ranges, referred to here as High Asia. These mountain ranges are located within the countries of Bhutan, Nepal, China, India, Pakistan, Afghanistan, Kazakhstan, Uzbekistan, Kyrgyzstan and Tajikistan. These countries, containing the headwaters of the Brahmaputra, Ganges, Indus, Syr Darya and Amu Darya rivers, all possess significant snow and ice resources. The amount, timing and spatial patterns of snow and ice melt play key roles in providing water for downstream irrigation, hydropower generation and general consumption. Water security in such high-altitude regions of the world is par-ticularly sensitive to climate change because of the significant role of snow and glaciers.