Everest snow line rose 490 feet in less than two months, increasing from 20,000 feet on December 11, 2024, to 19,510 feet on January 28, 2025. This change was attributed by scientists to sublimation, a process in which snow evaporates directly into the atmosphere due to powerful winds, low humidity, and unseasonably warm temperatures. Mauri Pelto, a glaciologist and member of the science advisory board for NASA Earth Observatory, noticed the shift using data from local weather stations and satellite imagery.

Long-Term Trends and Climate Patterns

Seasonal snow is now only seen at higher elevations, according to scientists, as warmer and drier weather is pushing the winter snow line higher. This upward retreat was corroborated by NASA’s Landsat 9 satellite images taken on January 20, which contrasted sharply with the normal snow distribution seen in January 2022. Experts pointed out that recent winters have seen sparse lower-elevation snow, as was the case last January. Pelto noted that this pattern has continued for several years, suggesting a “new normal” for the area. He explained that sublimation, not melting, was the cause of the most recent change.

After an exceptionally warm and wet post-monsoon season and a dry start to 2024, the snow line had already been higher than average at the beginning of winter. The only recent year that January snow lines stayed at normal levels, according to Pelto, was 2022. Nonetheless, higher snow lines in January 2021, 2023, 2024, and 2025 point to a long-term change in snowfall patterns. In contrast to glaciers in North America and Europe, which build mass from winter snowfall, Himalayan glaciers mostly accumulate snow during the summer monsoon. For this reason, dry winter months are particularly important for the long-term health of glaciers.

Also Read: U.S. EPA Grants Authority To West Virginia To Manage Carbon Capture

Potential Consequences for Water and Fire Risks

Experts caution that there may be dire repercussions if the Himalayan winter snow line rises to previously unheard-of heights. The Everest snow line rose 490 feet in less than two months, signaling an alarming trend driven by sublimation. Higher snow lines could jeopardize water security for populations downstream that depend on glacial melt for their freshwater supply. As demonstrated by Nepal’s early 2025 fire season, reduced winter snow cover could raise the risk of wildfires, further worsening environmental vulnerabilities.

Also Read: Seattle Advocates Promote Social Housing As A Climate And Equity Solution