Melting glaciers threaten Huaraz, Peru

At first glance, Lake Palcacocha doesn't look any more or less dangerous than the other bodies of water in its vicinity. But perched where it is atop a high Andean gorge, it threatens Huaraz, the Peruvian city of 150,000 in the valley below. Climate change has swollen Lake Palcacocha with glacial meltwater. If a big chunk of the nearby glacier were to fall in, it would send a flood wave as high as 30 meters (100 feet) churning with mud and boulders towards the city. In 1941 nearly 1,800 people died in Huaraz when icefall triggered such a flash flood. For now, no flood mitigation measures are in place. Instead, 10 tubes pump excess water out of the lake. One man stands watch, radioing in the status of Lake Palcacocha every two hours.

Caroline Binley