Fears Grow of a Himalayan Tsunami as Glaciers Melt
Melting glaciers and rising temperatures are forming a potentially destructive combination in the deep ravines of Nepal’s Himalayan foothills, and the Phulping Bridge — on the Araniko Highway linking Kathmandu with the Chinese border — is a good place to see just how dangerous the pairing can be.
A bare concrete pillar stands there, little noticed by the drivers of trucks, laden with Chinese goods, that rattle along at high speeds across the bridge, about 110 km from Kathmandu. The pillar is all that’s left of the original Phulping Bridge, which was swept away by floodwaters in July 1981. The deluge was not caused, as is common, by monsoon rain, but by the bursting of a glacial lake. The force of the raging torrent was strong enough to dislodge boulders 30 m across. They still lie in the Bhote Koshi River.
Glacial-lake outbursts, as they’re known, are not new. They occur every time the natural dams of ice or accumulated rocky deposits that hold back glacial lakes give way because of seismic activity, erosion or simple water pressure. Millions of cubic meters of meltwater can be released as a result, sometimes over the course of a few days or — far more frighteningly — in a matter of minutes. During the past century, at least 50 glacial-lake outbursts were recorded in the Himalayas, according to data maintained by the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD). But what is new is that the lakes are forming and growing much more quickly because the glaciers are melting faster than ever.