India, Aug. 29 -- Picture this. It's nine in the morning. Along the Trishuli River, the shops are opening as they do on any day; pilgrims are setting out for Kailash; labourers have begun the day's shift on the hydroelectric projects. It looks like one more ordinary morning. And then the mountain roars.

On the morning of the twenty-sixth of August, high above the Lhende river in Tibet, some twenty kilometres north of the Nepal border, a vast slab of ice and rock broke away from a glacier and fell into the river below, damming it. The water stopped, gathered, rose, and when enough of it had gathered it burst the wall it had made and came down all at once into Nepal's Rasuwa district, carrying everything away: whole villages, the bridges, ...