Scientists studying the glaciers around Mt. Everest have noticed a concerning trend: the snow line has moved up by 490 feet in just two months, from 20,000 feet on December 11, 2024, to 19,510 feet by January 28, 2025. This change is due to a process called sublimation, where snow turns directly into water vapor without melting. Unlike melting, sublimation happens when strong winds, low humidity, and warm temperatures are present.
Research from Colorado State University calls sublimation a “mysterious” process, as it is difficult to measure and understand. Scientists warn that if this continues, the snow line could rise even further in future winters. According to glaciologist Mauri Pelto, warmer and drier conditions are pushing the snow line higher. NASA’s Landsat 9 satellite images from January 20, 2025, show that snow levels at mid-altitudes are lower compared to January 2022.
Pelto’s research suggests that this is part of a long-term trend, with similar patterns seen in 2021, 2023, and 2024. The only exception was in 2022 when snow levels stayed stable. Unlike glaciers in Europe and North America, which gain mass from winter snowfall, Himalayan glaciers mainly get their snow during the summer monsoon, making winter snow especially important for their survival.
The rising snow line could lead to serious consequences, such as shrinking glaciers, reduced freshwater supply, and drier conditions that may cause more wildfires in the future.
