Climate change is rapidly altering the Himalayan environment, with glaciers melting, snow and ice declining, and risks of rockfalls and sudden floods increasing. On Wednesday, a glacier and part of a mountain collapsed on the northern side of 23,734-foot Langtang Lirung near Nepal’s Tibet border, sending water, mud and rocks across about 60 miles. Weeks earlier, an avalanche on Broad Peak in Pakistan’s Karakoram range killed 10 climbers, including Nepali mountaineer Nirmal Purja.

Tribhuvan University glacier researcher Aravindra Khadka said Himalayan glaciers are losing an average of about one metre of ice each year. Mountain guide association president Tula Singh Gurung said retreating snow and ice are exposing bare rock and making routes unfamiliar, while rockfall risks are emerging across many areas. Experts said further research is needed to establish the precise cause of the Langtang disaster.

The changes also threaten Nepal’s tourism-dependent mountain economy. Tourism accounted for 6.1 percent of the economy and nearly 1.2 million jobs in 2023, according to the World Bank. Climbers increasingly use weather forecasts, GPS, avalanche detectors and drones, which may reduce risks for Sherpas and other local workers as autumn trekking approaches.