Nepal's quake-driven landslide hazards: Large earthquakes can trigger dangerous landslides across a wide geographic region. The 2015 M _w 7.8 Gorhka earthquake near Kathmandu, Nepal, was no exception. Kargal et al. used remote observations to compile a massive catalog of triggered debris flows. The satellite-based observations came from a rapid response team assisting the disaster relief effort. Schwanghart et al. show that Kathmandu escaped the historically catastrophic landslides associated with earthquakes in 1100, 1255, and 1344 C.E. near Nepal's second largest city, Pokhara. These two studies underscore the importance of determining slope stability in mountainous, earthquake-prone regions. Science , this issue p. 10.1126/science.aac8353 ; see also p. 147

Mountain ranges in Asia are important water suppliers, especially if downstream climates are arid, water demands are high and glaciers are abundant. In such basins, the hydrological cycle depends heavily on high-altitude precipitation. Yet direct observations of high-altitude precipitation are lacking and satellite derived products are of insufficient resolution and quality to capture spatial variation and magnitude of mountain precipitation. Here we use glacier mass balances to inversely infer the high-altitude precipitation in the upper Indus basin and show that the amount of precipitation required to sustain the observed mass balances of large glacier systems is far beyond what is observed at valley stations or estimated by gridded precipitation products. An independent validation with observed river flow confirms that the water balance can indeed only be closed when the high-altitude precipitation on average is more than twice as high and in extreme cases up to a factor of 10 higher than previously thought. We conclude that these findings alter the present understanding of high-altitude hydrology and will have an important bearing on climate change impact studies, planning and design of hydropower plants and irrigation reservoirs as well as the regional geopolitical situation in general.

The cryosphere is defined by the presence of frozen water in its many forms: glaciers, ice caps, ice sheets, snow, permafrost, and river and lake ice. In the extended Hindu Kush Himalaya (HKH) region, including the Pamirs, Tien Shan and Alatua, the cryosphere is a key freshwater resource, playing a vital and significant role in local and regional hydrology and ecology. Industry, agriculture, and hydroelectric power generation rely on timely and sufficient delivery of water in major river systems; changes in the cryospheric system may thus pose challenges for disaster risk reduction in the extended HKH region.

Waters of high Asia: How the rivers of the Himalaya-Karakoram region of Asia respond to climate change is critical for the billion-plus people who depend on the water that they provide. In a review, Azam et al . discuss recent progress in understanding the importance of glacier and snow melt in the hydrological budget there, which is driven largely by advances in remote sensing and modeling. Observational data remain sparse and challenging to collect. —HJS

Previous geodetic estimates of mass changes in the Karakoram revealed balanced budgets or a possible slight mass gain since ∼ 2000. Indications of longer-term stability exist but only very few mass budget analyses are available before 2000. Here, based on 1973 Hexagon KH-9, ∼ 2009 ASTER and the SRTM DTM, we show that glaciers in the Hunza River basin (central Karakoram) were on average in balance or showed slight insignificant mass loss within the period ∼ 1973–2009. Heterogeneous behaviour and frequent surge activities were also characteristic of the period before 2000. Surge-type and non-surge-type glaciers showed on average no significantly different mass change values. However, some individual glacier mass change rates differed significantly for the periods before and after ∼ 2000.