Explained: How glaciers, glacial lakes form and why they break

The floods that slammed into two hydroelectric plants and damaged villages in Uttarakhand were set off by a break on a Himalayan glacier upstream. Here's a look at how glaciers and glacial lakes form and why they may sometimes break: How glaciers and glacial lakes form Glaciers are found on every continent except Australia and some are hundreds of thousands of years old. “Most mountain glaciers around the world were much larger in the past and have been melting and shrinking dramatically due to climate change and global warming,” said Sarah Das, an associate scientist at Woods Hole Oceanographic Institute. “There are many glaciers and glacial dammed lakes across the Himalayas, but most are unmonitored,” Dr. Das said. A 2010 information page published by the International Centre for Integrated Mountain Development called for more glacier monitoring in the Hindu Kush Himalayas to better understand “the real degree of glacial lake instability.” The region where the glacial burst occurred is prone to landslide and flash flooding, and environmentalists have cautioned against building in the region.