Credit: The ASSOCIATED PRESS
Catastrophic Glacial Lake Outburst Floods (GLOF) have occurred in many mountain ranges throughout the world at different times in world history. In some instances, these mountain tsunamis have caused extensive damage and loss of life further downstream. What is new now is that we have never experienced so many potentially dangerous melt water glacial lakes in such a short period of time nor have we seen how quickly these lakes now grow. Climate change contributes to the formation of these lakes by unseasonal rains, particularly in the Himalayas, where the Monsoon season starts earlier then in years past, the frequency of and volume of the rains or cloudbursts is increasing with rainfall exceeding at times 300% of normal precipitation. Warmer temperatures caused by climate change mean that snowfall that once began in October now arrives in January. and that leaves too little time for it to harden into more heat-resistant ice. So when summer returns, the volume of meltwater is much larger. Most insidiously by a climate-induced glacial instability that, in future years, threatens to wreak havoc across the Himalayas, and to a smaller extent the Alps, Andes and Rockies.
Per the International Center for Integrated Mountain Development.
The Hindu Kush-Himalayan (HKH) region embraces the greatest agglomeration of high mountains and plateaus in the world. It consists of many distinct but inter-connected mountain ranges and plateaus extending for about 3,500 km from the Hindu Kush of Afghanistan and Pakistan in the northwest, through the Himalayas of India, Nepal, and Bhutan in the central part, to the Hengduan Mountains in southwest China in the east. It contains the world’s highest mountains, many above 8,000 metres, together with the world’s greatest areal extent and volume of permanent ice and permafrost outside the polar regions. Without doubt, it is central for any understanding of the effects of the current climate warming. One special element of the process of climate warming is its impact on the glaciers, and especially on the development of potentially dangerous glacial lakes within the Hindu Kush-Himalaya region.
Glacial lakes are potentially unstable because their end moraines are composed of unsorted and unconsolidated boulders, gravels, sands, and clays. Furthermore, they are frequently reinforced by frozen cores (permafrost) that, like the glaciers themselves, are now beginning to melt. As the volume of a lake that is accumulating behind an end moraine increases, hydrostatic pressure builds up to put additional stress on the moraine dam causing it to become more unstable. Eventually it may fail and release much, or all, of the lake water. Depending on the manner in which the dam fails, the ensuing outbreak of water can be sudden and highly dangerous to people and infrastructure located downstream. The surging flood water will often have the energy to entrain large masses of loose material (boulders, gravel, sand, and clay, as well as any broken masonry or torn out trees) as it is propelled down-valley.
Credit: David Putnam
Tshewang Rigzin (Department of Hydromet Services, Royal Government of Bhutan) and guides sampling boulder on moraine.
Ironically, with more water now cascading through Himalayan valleys, climatologists fear the heavily populated downstream regions of Pakistan, Bangladesh and India will soon suffer from water shortages as the glacial ice becomes depleted.
Glacial time bombs
Aside from the stronger rains and the later snowfall, melting glaciers are literally transforming the Himalayan landscape at an unprecedented rate.
An hour or two before the flash flood forced Bhist and the other labourers to scramble for safety, scientific observers at Chorabari Lake, about 2.5 kilometres upstream from Kedarnath, heard a loud bang, according to Dobhal. It had already been raining for days, and millions of litres of water had accumulated in the lake.
Now, Dobhal speculates the bang may have been the noise of an avalanche or landslide that knocked loose the natural dam of ice and rock holding back the lake — draining it in minutes and sending the full force of the waters down onto the town below.
It won’t be the last such disaster, experts fear.
Across the region, rising temperatures are fast creating thousands of such lakes. And the growing volume of meltwater is dangerously increasing the risk of sudden glacial lake outburst floods, according to the Kathmandu-based International Center for Integrated Mountain Development.
“When you talk about glacial lakes, in Nepal alone there are more than 1,400 lakes. And if you talk about the whole Himalayan Range . . . there are about 20,000 glacial lakes,” says Pradeep Mool, who monitors the risk of glacial lake outbursts for the mountain development centre.
More than 200 of these lakes have been classified as potentially dangerous.
Lost lives, lost livelihoods
Today, the tourists and pilgrims have been evacuated from Uttarakhand. But government officials and aid workers are still coping with the tragedy’s impact.
With the destruction of the roads and bridges connecting many villages to larger towns and cities, tens of thousands of people are now forced to hike for basic supplies such as rice and flour. Moreover, their renewed isolation threatens to erase the economic gains that come from access to markets and labour centres.
“We have villages that got totally destroyed,” said Aditi Kaur, 43, who heads the non-profit Mountain Children’s Foundation. “The river has just become so wide now, (and) the flow was so swift, that there is no rubble left to see.”
“The fields just disappeared into the river so the food-grain you are growing for the next year is not going to be there. The disaster that has happened today is also affecting tomorrow and a year from now.”
Worse still, in some of these villages, all of the men worked in Kedarnath during the pilgrimage season, so there are countless families whose fathers, husbands and brothers have all been lost.
Because few village women have ever left their fields and livestock for paid jobs — though all of them work from sunrise to sunset — a loss of husband and father means the loss of the family’s sole breadwinner.
Climate change is partly to blame for the rains last June that heavily damaged the pilgramage town of Kedarnath and its majestic eight-century temple dedicated to Shiva, the Hindu god of destruction.
It was a multiday cloudburst over the northern part of the Uttarakhand and adjourning Himachal Pradesh that caused sudden massive flash flood associating landslide and earth flow. From 14 to 17 June 2013, this area received heavy rainfall (370 mm In Dehra Dun 16 th 17 th June), which was about 375 percent more than the benchmark rainfall during normal Monsoon. [3] Main affected area was Kedarnath. After cloud burst, the Chorabari Lake (3800 meters) was collapsed resulting flash flood in Mandakini River
redOrbit reports
These massive glacier-capped mountains, often referred to as the water towers of Asia, are the headwaters for several major river systems, including the Yellow, Yangtze, Mekong and Ganges rivers, among others. All told, nearly one quarter of the Earth´s population relies on these glaciers for drinking water and irrigation.
A prolonged glacier retreat would both increase the volume of water in the rivers as well as the levels of sediment that they carry, which could choke water supply and disrupt agriculture, the study says.
In this study, the Gravity Recovery and Climate Experiment (GRACE) satellite mission was used to create models to extrapolate data about the melt and its potential effects. Thompson says it is also important to look at the longer-term picture because climate is generally considered a 30-year average of weather trends.
As an example, the Naimona´nyi Glacier that feeds the Indus River shrank by 508 feet during a 30-year sample period, or about 16.4 feet annually.
“We were surprised to find that at 19,849 feet [where the glacier is located] there had been no net accumulation [of ice] since the late 1940s,” Thompson told IRIN, the news service of the U.N. Office for the Coordination of Humanitarian Affairs.
Many experts speak of an impending tipping point in global warming, a time when humans will no longer be able to repair or even affect the trajectory of the earth´s climate. These reports indicate that something drastic is occurring. The effects are increasingly visible and the cost of seeming inaction and political paralysis may be the legacy we never get to leave behind.
