On June 29, 2026, the snow that had accumulated on Switzerland’s glaciers during the previous winter completely melted, marking what is known as Glacier Loss Day. This date indicates the start of a period of continuous melting until snow begins to accumulate again in the fall. According to Matthias Huss, head of Glacier Monitoring in Switzerland (GLAMOS), this year’s Glacier Loss Day arrived three months earlier than it would in a "healthy" climate, signaling a concerning trend in glacier health. Inspired by Earth Overshoot Day, which marks when humanity has used up Earth’s annual ecological resources, Glacier Loss Day serves as a clear indicator of the broader warming trends affecting the Alps. This year’s date was the second-earliest on record, only three days later than in 2022, when glaciers lost about 6% of their total mass. Experts attribute this year’s early and rapid melting to two consecutive heat waves across Europe in June and July, which pushed temperatures above 40°C (104°F) in parts of central Europe. In the Alps, the daytime freezing level—the altitude where temperatures reach 0°C—rose to 4,500 meters (14,800 feet) in June, meaning snowline moved higher than ever. With little overnight refreezing, the risk of avalanches and unstable slopes has increased. In the Mont Blanc massif, aerial images reveal that the Bossons Glacier, which overlooks the French alpine town of Chamonix, is experiencing significant melting. Meltwater streams now flow down the valley where the glacier once touched the ground in the 1980s. A large cavity first observed in 2025 remains visible more than a year later, a sign of the glacier’s rapid retreat. The reduced snowfall over the past decade has also played a role. During the 2025–26 winter, snow depths in the central European Alps were among the lowest in the last 30 years. Less snow means less reflection of sunlight, exposing darker ice that absorbs more heat and accelerates melting. The Rhône Glacier in the Swiss Alps lost over 4 meters (13 feet) of ice in June and July 2026, and as of July 2026, it is losing 10 centimeters of ice per day on average. Meltwater is widening cracks and creating cavities, which could lead to more instability in the glacier’s lower regions, similar to what is observed at Bossons. The impacts of this glacial melting extend beyond the mountains. The Rhône Glacier feeds the Rhône River, which flows through Switzerland and France, providing drinking water for about 2.5 million people and supporting agriculture for millions more. While early-season runoff from melting glaciers can temporarily ease drought conditions, prolonged melting threatens water security in late summer when glaciers no longer contribute significantly to river flow. In the French Alps, the Grande Motte Glacier, which supports summer skiing at the Tignes ski resort, is shrinking rapidly. The resort has already shortened its summer ski season due to unsafe conditions, and officials warn that summer skiing could disappear within 10–15 years. Efforts to use artificial snow to extend the season are seen by some experts as a temporary solution that may lock communities into an unsustainable economic model. Similar challenges are emerging in Italy, where mountain guides have stopped using the Miage Glacier route on Mont Blanc due to the increased danger from melting ice and unstable terrain. As heat waves become more frequent and intense, the glaciers and the alpine economies they support are likely to be among the first and most visible victims of global warming.