As the black clouds heavily pregnant with water vapour hovered over Dehradun on June 15, 2013, it looked ominous. Around 13,000 feet above the sea level, rain was already tanking up Chorabari Lake, a water body created by melting glaciers. On June 16 midnight, the heavy rain caused the lake’s rock bank to collapse, sending down a flash flood that swept through the holy Himalayan pilgrimage site Kedarnath, killing 5,000 people.
There are 1,266 such Chorabari lakes in Uttarakhand’s Himalayan regions, some of which have been created fresh by the rapid retreat of glaciers due to global warming, found a study by Wadia Institute of Himalayan Geology, an autonomous body of the central government.
These lakes are of different sizes — the smallest is of 500 square metres and the biggest of 2.4 lakh square metres, which is roughly 20 football fields put together — and are mainly scattered between the Bhagirathi and Alaknanda river basins, the two head streams of the Ganga, says the report titled ‘Glacier Lake Inventory of Uttarakhand’. But it is not the size, but the amount of water in a glacier lake that decides how deadly it is.
According to the report, a few lakes have the potential to bulk up further and burst under the slightest provocation of weather, threatening the human population and infrastructure downstream the rivers just like 2013 when Chorabari lake sent water crashing into Mandakani, a tributary of the Ganga.
Scientists engaged in the study said there seemed to be no immediate threat to human population from these lakes but they have to be constantly monitored.
DP Dobhal, the senior glaciology scientist of Wadia Institute, said: “Present study shows that glacier lakes are not very large in size but those formed by retreating glaciers mainly owing to climatic changes triggered by global warming can have damaging impact in future”.
“Their constant monitoring is needed in order avoid any future disaster-like situation,” said Dobhal
The study identifies 809 lakes as ‘ice dammed lakes’ meaning lakes surrounded by ice on all sides. 329 lakes are ‘moraine dammed lakes’, which are bordered by boulders and sediments -- and more dangerous. Around 635 lakes have been found in the Alaknanda river basin glaciers alone.
“For instance, the government must keep track of variations in Satopan and Yamunotri glacier lakes above Badrinath and Yamunotri temples. These are lakes bordered with large-size boulders and rocky materials similar to Chorabari lake above Kedarnath,” said AK Gupta, the director of Wadia Institute of Himalayan Geology.
“Several glacier lakes that have been identified in the study are located at places where human population exists. Now it’s for the stake holders or policy makers to take necessary measures,” said AK Gupta, the director of Wadia Institute of Himalayan Geology,
“We have provided a copy of out report to the state government,” he said.
The state government has sought better coordination between the central government institutions and state government in sharing information that will help state in framing its policies.
Chief minister Harish Rawat said: “There is no one to inform the state government about the latest status of Chorabari lake that caused disaster in 2013 at Kedarnath. Neither have we been informed about lake formation beyond Hemkund Saheb shrine”.
“There is a need for greater coordination between the Centre and the governments in sharing information like formation of glacier lakes in the state as only central government institution have expertise to identify them,” said Rawat.