In the far north of India, a cold mountain desert is the stunning backdrop to an unprecedented icy structure. This is a land of extremes, where rainfall is scarce and temperatures range wildly from torrid to far below freezing. The locals say it’s the only place in the world where a man, sitting in the sun with his feet in the shade, can suffer sunstroke and frostbite at the same time.
It’s the Ladakh region – meaning “land of high passes” – sandwiched between two of the world’s tallest mountain ranges, the Himalayas and the Kunlun.
Rainfall is rare here. Water, essential for irrigating the farmlands that are the lifeblood of the local population, mostly comes from melting snow and ice.
But climate change is making this land even drier, leaving farmers without water in the crucial planting months of April and May, right before the glaciers start to melt in the summer sun.
One man’s solution to the problem? Make more glaciers.
The ‘Ice Stupa’
In 2014 a local mechanical engineer, Sonam Wangchuk, set out to solve the water crisis of the Ladakh.
The natural glaciers are shrinking due to rising global temperatures. For that reason, they provide far less water in early spring but then release a lot in the summer heat, shrinking even more.
Wangchuk had a simple idea: he wanted to balance this natural deficit by collecting water from melting snow and ice in the cold months, which would normally go to waste, and store it until spring, just when farmers need it the most.
“I once saw ice under a bridge in May and understood that it’s the sun that makes the ice melt, not ambient temperature,” he told CNN.
“I realized that ice can last a long time, even at low altitudes.”
He then built a two-story prototype of an “ice stupa”, a cone of ice that he named after the traditional mound-like sacred monuments that are found throughout Asia.
Why a cone?
The ice stupa is created using no power or pumps, only physics: “the ingredients are a downstream, an upstream and a gradient,” says Wangchuk.
First, a pipe is laid underground, connecting a stream of water and the location where the ice stupa is required, usually next to a village. The water must come from a higher altitude, usually around 60 meters or more.
Because a fluid in a system always wants to maintain its level, water from 60 meters upstream will spray 60 meters into the air out of the downstream pipe, creating a fountain.
The freezing air temperature does the rest, immediately crystallizing the water droplets into ice that falls right below, forming a cone.
“A cone is very easy to make with ice, because any dripping naturally forms a cone underneath – icicles are inverted cones,” says Wangchuk.
But a cone has more desirable properties: “It has minimal exposed surface area for the volume of water it contains.”
That means it melts very slowly: the prototype, 20 feet tall and containing 150,000 liters of water, lasted from winter until mid-May, just when water is needed for irrigation, while all the surrounding ice on the ground had gone by the end of March.