Glacier Lake Floods
Listen in RealAudio
Email Your Comments

Dave Thurlow, Host
In parts of the Himalayas, there has been a shortage of precipitation over the last 40 years. But there's also a potential for major flooding. Why? Hi, I'm Dave Thurlow and this is The Weather Notebook.

A large terminal moraine was formed by a
standstill of a glacier in the early 20th century.
Tulsequah Lake, Northwestern British Columbia.
Photo by Marten Geertsema,
British Columbia Ministry of Forests

The Himalaya is home of many of the world's glaciers. There's been a lack of snow and rainfall there, and temperatures are rising. Therefore, glaciers are shrinking 20 feet a year.

Here's Cameron Wake, a climatologist from the University of New Hampshire.

CW: Right now, as the glaciers are melting, there's a steady supply of meltwater from these glaciers. But if, in fact, precipitation is decreasing in that region, there's going to come a point in time when there's not enough ice left to melt and that could dramatically impact the water supply in that area.

Another concern is that as the glaciers retreat, they leave behind long piles of rock called moraines that look and act like dams. They fill up with meltwater coming off the glacier. And like dams, they can break:

CW: And you have what we call glacier lake outburst floods. And one example is in the 1980's there was a glacier dam lake that formed in the Khumbu region, the Mount Everest region of Nepal and there was actually construction being completed on a hydroelectric power plant. And there was either a large avalanche or a large glacier fell into the lake and the water in the lake basically was just forced over the moraine dam and flowed downstream and it actually completely wiped out the entire hydro-electric plant, as well as several villages.

The department of hydrology and meteorology in Nepal is now working on a way to drain the lakes to avoid such catastrophes, but there is nothing to be done about the retreating glaciers.

Our show is made possible by Subaru and the National Science Foundation.

Related Links

Glaciers and Glaciations

Glacial Landforms and Features