Climate change and poor planning create disaster

Himalayan floods are natural, but poor planning turns rain into disaster. Reading the land could save lives, says Manudeo Singh of Aberystwyth University

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ON AUGUST 5, a cloudburst near the Kheer Ganga river triggered a flash flood that tore through Dharali, a village in the Indian Himalayas.

Within minutes, the river swelled with water, mud and debris, sweeping away homes, roads and lives.

Every monsoon season, the Himalayas see similar tragedies flash floods caused by cloudbursts or glacial lake outbursts.

The first explanation we often hear is climate change. Extreme rainfall and melting glaciers are part of our warming world, but that is only half the story. The other half lies in where and how we build.

A cloudburst is an extreme, sudden downpour often more than 100mm of rain in just an hour, falling over a small area. It's like the sky suddenly emptying a huge bucket of water over the mountainside.

A glacial lake outburst flood happens when a lake formed by melting glaciers bursts through its natural dam of ice or loose rock, releasing a sudden torrent downstream.

Both cloudbursts and glacial lake outbursts send huge volumes of water rushing down steep valleys. On their way, they pick up mud, rocks and trees, turning into debris-laden flash floods that sweep away whatever lies in their path.