In minutes, rushing water can transform a swollen river into a destructive wall. In Nepal,
experts say flash flooding has shown just how quickly a catastrophic collapse can trigger the most violent flash flood in modern history.
This wasn’t the standard slow-rising flood, because at the altitude of 17,000 feet in the Himalayas, a section of a glacier snapped completely off a cliff face. As a result, between 100 million and 200 million cubic meters of ice rock dropped vertically down the mountain.
The friction of the falling ice and rock generated extreme heat, resulting in the ice melting quickly. The ice rock created a block in a narrow gorge and from intense pressure the gorge burst and released the devastating “water bomb” down the Bhote Koshi River Valley.
The 20 billion liters of fluid released could fill 8,000 Olympic-sized pools.
The Himalayan valleys are tight, steep, and V-shaped causing the energy of the surge to be tightly compressed and with nowhere to expand outward the liquid concrete wall of debris forced its way straight up.
Satellite data indicates that debris reached heights of 130 to 300 feet as it squeezed through the gorge. The water height itself peaked at 300 feet — nearly as tall as the Capital Center building in downtown Columbia, which is 349 feet.
The sheer force of the water — moving at 105 mph — meant that multi-story concrete structures stood no chance as it elevated high above the normal riverbed. As a result of this catastrophic flood, Nepal and Tibet has faced significant loss, with more than 1,000 confirmed fatalities and more than 4,400 people still missing, including tourist. More than 7,000 homes have been swept away, 19 critical bridges destroyed, and entire mountain villages buried under the thick soil.
For Nepal and Tibet, this was more than a flood. It was a loss of homes, livelihoods and loved ones, in minutes.
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