Compiled by Outside Online

April 17, 2002 United Nations scientists say more than 40 Himalayan glacial lakes could soon burst their banks and dump millions of gallons of floodwaters into inhabited valleys, causing loss of life and severe damage to infrastructure.

After surveying nearly 5000 Himalayan lakes using satellite images, aerial photographs, and topographic maps, researchers from the United Nations Environmental Program and the International Center for Integrated Mountain Development found 20 in Nepal and 24 in Bhutan that pose immediate threats. The lakes, formed by melting glaciers and snowfields, could burst within five years. Hundreds of other lakes remain unsurveyed.

The melting is caused by rising regional temperatures attributed to global warming, according to the study.

While hundreds of thousands of lives are at risk, there are other concerns. Severe floods could cause millions of dollars worth of property damage to roads, bridges, agricultural sites, hydroelectric plants, tourism facilities, and trekking trails —the economic life-blood of many countries in the region.

Glacial lake outburst floods (GLOFs) are not a new phenomenon, but the study suggests that their frequency has risen in the past thirty years.

"These glacial lake outbursts used to be events that happened once every 500 years, but they have become frequent since 1950," Surendra Shrestha, Regional Coordinator in Asia for UNEP's Division of Early Warning and Assessment told NewScientist.com.

In August 1985, a sudden flood from the Dig Tsho glacial lake in Nepal destroyed 14 bridges and $1.5 million worth of damage was caused to the nearly completed Namche Small Hydropower Plant.

UNEP says that with aid from foreign governments it's working to lower hazardous water levels in lakes and construct early warning systems for threatened communities. However, regional coordinators fear that a lack of funding will hamper their efforts to solve the problem at many of the remote lakes.