Himalayan Tsunamis

[Guest guest]

was sponsored by the Kathmandu-based ICIMOD and the China Meteorological

Administration. ICIMOD already has a regional flood initiative for exchanging

hydrological data but says Himalayan flashfloods need even greater crossborder

cooperation because many of the steep rivers flow across boundaries and

reaction time is measured in hours, not days. “Major Himalayan rivers are

transboundary river basins and flashfloods will not respect national borders,”

says Xu Jianchu, a Chinese scientist with ICIMOD, “that is why we need to think

regionally and act locally.” Indeed, an existing bilateral early warning

mechanism between India and China prevented what could have been a catastrophe

on the Sutlej River in February this year. By the time flood waters surged

through Himachal Pradesh, people had been

evacuated and no lives were lost. Similarly, despite strained relations between

India and Pakistan they share warning through radio broadcasts and this

prevented another potentially devastating loss of life on the Chenab earlier

this year. However, officials say a lot more needs to be done to map hazardous

valleys, glacial lakes in Bhutan, Nepal and Tibet that are in danger of bursting

and to transmit rainfall data in real time so downstream regions have time to

evacuate. “There is a lack of exchange of real time data and there needs to

be a regional mechanism for this,” says Mandira Shrestha, a water resource

specialist at ICIMOD. Although Nepal has got the most experience in the region

in mapping and draining glacial lakes, our

domestic warning system for big rainfall events is almost non-existent which is

why flashfloods triggered by cloudbursts in the central midhills during

monsoons in 1981, 1993, 2002 and 2003 were so catastrophic. “There is no

operational flood-forecasting in Nepal,” says Arun Bhakta Shrestha of the

Department of Hyrdology and Meteorology.. Pradeep Mool of ICIMOD is an

international expert on glacial lake outburst floods (GLOFs) and says there is

now little doubt that climate variability is causing rapid glacial retreat,

especially in the eastern Himalaya. The frequency and damage caused by GLOFs

have been increasing due to climate change, and Mool is working with Chinese

scientists to study several lakes in Tibet that drain into the Trisuli and

Bhote Kosi that are in danger of bursting. The Bhote Kosi Power Company has

installed sensors all the way up to the Chinese border that gives the 46 MW

project five minutes warning in case of a GLOF. There are 42 glacial lakes in

the Bhote Kosi basin in Tibet and the river has a history of flashfloods. “What

we’d like is to have sensors further upstream and extend the warning time,” says

Bhote Kosi’s Sandip Shah. There have been 25 glacial lake floods recorded in

Nepal and more than half of them originated in Tibet. Of the 2,315 glacial

lakes within Nepal, 20 are said to be extremely dangerous. And one only needs

to look at geological evidence of past events to see the kind of damage they

can cause. Pokhara is situated on the debris field of a catastrophic flashflood

on the Seti some 800 years ago which if it happened today could cause up to

200,000 deaths. Average temperatures across the mountains

are increasing at 0.06 degrees a year. Glacial lakes that used to be small ponds

20 years ago are now 5 sq km and larger. Closer cooperation between China and

Nepal could protect downstream infatructure and towns in Nepal not just in the

Bhote Kosi but the Trisuli and Arun as well. Says ICIMOD Director General J

Gabriel Campbell: “We must make information travel faster than flashfloods.”

Himalayan Tsunamis ROBIN MCKIE The lake on the terminal moraine of the

receding Gangapurna Glacier in Manang. Nawa Jigtar was working in the

village of Ghat in Manang when the sound of crashing sent him rushing out of

his house. He emerged to see his herd of cattle being swept away by a wall of

water. Jigtar and his fellow villagers were able to scramble to safety. They

were lucky: “If it had come at night, none of us would have survived.” Ghat

was destroyed when a lake, high in the Annapurnas, burst its banks. Swollen

with glacier melt its walls of rock and ice had suddenly disintegrated. Several

million cubic metres of water crashed down the mountain. When Ghat was destroyed

in 1985

such incidents were rare. Not any more. Last week, scientists revealed that

there has been a tenfold jump in such catastrophes in the past two decades, the

result of global warming. Himalayan glacier lakes are filling up with more and

more melted ice and 24 of them are now poised to burst their banks in Bhutan,

with a similar number at risk in Nepal. But that is just the beginning, a

report in Nature said. Future disasters around the Himalaya will include

floods, droughts, land erosion, biodiversity loss and changes in rainfall and

the monsoon. The roof of the world is changing, as can be seen by Nepal’s

Khumbu glacier, where Hillary and Tenzing began their 1953 Everest expedition.

It has retreated 5 km since their ascent. Almost 95 percent of Himalayan

glaciers are also shrinking and that kind of ice loss has profound

implications, not just for Nepal

and Bhutan but for surrounding nations, including China, India and Pakistan.

Eventually, the Himalayan glaciers will shrink so much their meltwaters will

dry up, say scientists. At the same time, rivers fed by these melted glaciers,

such as the Indus, Yellow and Mekong, will turn to trickles in the dry season.

Drinking and irrigation water will disappear. Hundreds of millions of people

will be affected. “There is a short-term danger of too much water coming out

of the Himalayas and a greater long-term danger of there not being enough,”

says Dr Phil Porter of the University of Hertfordshire. “Either way, it is easy

to pinpoint the cause: global warming.” According to Nature, temperatures in

the region have increased by more than 1 C recently and are set to rise by a

further 1.2C by 2050, and by

3C by the end of the century. This heating has already caused 24 of Bhutan’s

glacial lakes to reach ‘potentially dangerous’ status, according to government

officials. Nepal is similarly affected. “A glacier lake catastrophe happened

once in a decade 50 years ago,” said UK geologist John Reynolds, whose company

advises Nepal. “Five years ago, they were happening every three years. By 2010,

a glacial lake catastrophe will happen every year.” An example of the impact is

provided by Luggye Tsho, in Bhutan, which burst its banks in 1994, sweeping 10

million cubic metres of water down the mountain. It struck Panukha, 50 miles

away, killing 21 people. Now a nearby lake, below the Thorthormi glacier, is in

imminent danger of bursting. That could release 50 million cubic metres of

water, a flood reaching to northern India 150 miles downstream. Not only

villages are under threat: Nepal and Bhutan have built hydroelectric plants

selling electricity to India and these could be destroyed in coming years.

Worse, when Nepal’s glaciers melt, there could be no water to drive

run-of-the-river plants. A Greenpeace report last month suggested that the

region is already experiencing serious loss of vegetation.

http://www.nepalitimes.com/issue276/environment.htm#2

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