Scientists studying glaciers around Mt Everest have observed a concerning trend: the snow line has moved 490 feet higher in less than two months, from 20,000 feet on December 11, 2024 to 19,510 feet on January 28, 2025. This retreat happened due to a 'mysterious' process called sublimation, which is not melting, where sun and dry air can turn snow straight into water vapour.
Sublimation, unlike melting, is a process where snow evaporates directly into the atmosphere without melting, i.e molecules skip the liquid form and jump straight to a gas. This is driven by strong winds, low humidity and unusually warm temperatures, according to a Colorado State University research piece. The research also said that sublimation is "mysterious" as measuring it "is much harder to do".
Scientists have warned that if this trend continues, winters could see even higher snow lines.
What is causing sublimation on Everest?
According to glaciologist Mauri Pelto, a NASA Earth Observatory advisory board member, warmer and drier conditions are pushing the winter snow line higher, the Times of India reported. Seasonal snow is now settling at higher altitudes, as confirmed by satellite imagery from NASA's Landsat 9, which captured the snow distribution on January 20, 2025, the newspaper added. Compared to January 2022, this year's snow cover is lower at mid-level altitudes.
What are primary factors behind this shift in Everest snow line?
- A trend of increasing winter temperatures has been recorded in the Everest region.
- Winter precipitation is crucial for maintaining the snow line, but recent years have been drier than usual.
- Strong winds intensify the sublimation process, leading to snow loss before it can compact into ice.
Is this trend on Everest temporary or long-term?
Mauri Pelto's research suggests this is part of a long-term pattern, according to the newspaper. The snow line was already higher than average at the start of winter due to a dry beginning to 2024. Similar elevated snow lines were observed in January 2021, 2023, and 2024, indicating an ongoing shift rather than a temporary anomaly.
Only exception was in 2022 when the January snow line maintained at good levels.
Why Himalayan glaciers are different from European glaciers?
Unlike glaciers in North America and Europe, which gain mass from winter snowfall, Himalayan glaciers primarily accumulate snow during the summer monsoon (June to September). This makes winter snow particularly important for maintaining ice levels.
What are the consequences of higher winter snow line on the Everest:
- Less snow accumulation could lead to long-term glacial shrinkage.
- Changes in snow accumulation could impact freshwater supply.
- Dryer winter conditions could lead to more wildfires.
Discover the latest Business News, Sensex, and Nifty updates. Obtain Personal Finance insights, tax queries, and expert opinions on Moneycontrol or download the Moneycontrol App to stay updated!
