Glaciers are melting fast—putting millions at risk for flash floods

In mountain ranges around the world, glaciers are melting as global temperatures rise. Europe’s Alps and Pyrenees lost 40% of their glacier volume from 2000 to 2023. These and other icy regions have provided freshwater for people living downstream for centuries—almost 2 billion people rely on glaciers today. But as glaciers melt faster, they also pose potentially lethal risks. Water from the melting ice often drains into depressions once occupied by the glacier, creating large lakes. Many of these expanding lakes are held in place by precarious ice dams or rock moraines deposited by the glacier over centuries. Too much water behind these dams or a landslide into the lake can break the dam, sending huge volumes of water and debris sweeping down the mountain valleys, wiping out everything in the way. Today, over 10 million people across the world are vulnerable to glacial lake outburst floods.In High Mountain Asia alone, these flooding hazards are projected to triple by 2100, especially with continued high emissions.

Mar 27, 2025 - 09:40
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Glaciers are melting fast—putting millions at risk for flash floods

In mountain ranges around the world, glaciers are melting as global temperatures rise. Europe’s Alps and Pyrenees lost 40% of their glacier volume from 2000 to 2023. These and other icy regions have provided freshwater for people living downstream for centuries—almost 2 billion people rely on glaciers today. But as glaciers melt faster, they also pose potentially lethal risks.

Water from the melting ice often drains into depressions once occupied by the glacier, creating large lakes. Many of these expanding lakes are held in place by precarious ice dams or rock moraines deposited by the glacier over centuries.

Too much water behind these dams or a landslide into the lake can break the dam, sending huge volumes of water and debris sweeping down the mountain valleys, wiping out everything in the way.