Satellite Images Offer Clues to Causes of Glacial Lake Flooding

(from journal article: Field observations for glacial lakes: (a) the rapidly expanding Lake Longbasaba in 2012; (b) an areally increasing glacial lake at the Middle Rongbu Glacier near Mount Qomolangma (Everest) in 2008.)
(from journal article: Field observations for glacial lakes: (a) the rapidly expanding Lake Longbasaba in 2012; (b) an areally increasing glacial lake at the Middle Rongbu Glacier near Mount Qomolangma (Everest) in 2008.)

Satellites are now allowing us to track the behavior of icy glacial lakes on the Himalayan Mountains–in particular the conditions that lead to glacial lake outburst floods (GLOFs), which have become increasingly frequent in the region over the past 20 years.

Researchers from the Institute of Mountain Hazards and Environment and the State Key Laboratory of Cryosphere Sciences in China published a study in PLOS One in December of last year that catalogued data from lakes in the central Himalayas between 1990 to 2010.

The scientists, Drs. Yong Nie, Qiao Liu, and Shiyin Liu, used images from Landsat scientific satellites to count and measure glacial lakes in the region. As the longest running remote sensing project, Landsat has over 40 years of images available across the globe.

(from journal article: Distribution of glacial lakes in the central Himalayas)
(from journal article: Distribution of glacial lakes in the central Himalayas)

GLOFs – floods that occur when a lake dammed by a glacier or glacial moraine is released – are hazardous to communities located at elevations below the burst lake. Flooding and debris flows damage infrastructure, cause property loss, and can take lives, as GlacierHub has reported in prior posts. It is widely believed that rising temperatures due to climate change and reduced albedo of the ice from cryoconite (also known as carbon dust particles) are melting the glaciers at higher rates and causing lake volumes to rise, which in turn increases the risk of GLOF events. But the specific processes that lead to GLOF outbursts are not well understood.

By looking at lakes at four time points (1990, 2000, 2005 and 2010), at different elevations (from 3,500 to 6,100 meters), of different types (pro-glacial and supraglacial), and of varying sizes, the researchers were able to identify which lakes expanded faster and burst more frequently to understand which ones pose the greatest risk of GLOFs.

A GLOF from above in Alaska’s Kennai Peninsula (Travis S./Flickr, some rights reserved)
A GLOF from above in Alaska’s Kennai Peninsula (Travis S./Flickr, some rights reserved)

Overall, it was found that total lake surface area for the 1,314 lakes in the central Himalayas had increased over the 20-year period. Drs. Nie, Liu and Liu found that more lakes on the northern side of the central Himalayan range were expanding rapidly. They also found that pro-glacial lakes (lakes at the terminus of a glacier) grew faster than supraglacial lakes (lakes on the surface of the glacier). Some pro-glacial lakes are connected directly to glaciers while others are not, but those that were connected grew far faster. Additionally, larger pro-glacial lakes were likely to flood sooner than smaller ones and more changes to glacial lakes occurred at the altitudes between 4,500 and 5,600 meters.

The dynamics of alpine glacial lakes are complex, but this study could help communities monitor lakes at high risk of flooding and to create early-warning systems and disaster preparedness plans.

PAPER DOI: 10.1371/journal.pone.0083973.g002

GLOF aftermath in Peru ( Will McElwain/Flickr, some rights reserved)
GLOF aftermath in Peru (Will McElwain/Flickr, some rights reserved)

Glacier stories you may have missed – 9/08/14

(photo: Georgia Ministry of Internal Affairs)
(photo: Georgia Ministry of Internal Affairs)

Glacier Landslide Blocks Traffic between Russia and Georgia/Armenia


“On 20th August, another landslide occurred at the same site, once again blocking the Dariali Gorge.  This landslide, which is reported to have originated at the glacier, is reported to have been larger..”


Read more here.

Chilean Government Pressured Over Glacier Law

“Chilean NGOs and parliament members are putting pressure on President Michelle Bachelet’s administration to pass a new glacier protection law.”


Read more here.


Glaciers in China Have Shrunk by 15 Percent in 30 Years


“China’s state-run media reported  that the country’s glaciers have shrunk by 15 percent over the last thirty years because of, obviously, global warming.”


Read more here.



New book measures changes in China’s glaciers
The Number One Glacier in the mountains outside Urumqi, China, the largest glacier in Xinjiang province. The hydrological resources from glaciers like this one drive development in China’s remote northwest province. (Remko Tanis/Flickr)

In far northwestern China, in the province of Xinjiang, the Altai, Pamir, Kunlun, and Karakorum mountain ranges rise massively out of the earth, creating peaks that rival their famous neighbor to the south, the Himalayas. The mountains are home to some 18,000 glaciers, which have sustained the famous steppe nomadic hordes of antiquity with their annual summer melts into the rivers of the arid region.

These hydrological resources are driving the development of this remote province. A chapter from the recent book, Water Resource Research in Northwest China seeks to quantify the changes occurring to glaciers in Xinjiang.

The chapter’s authors, Zhongqin Li, Puyu Wang, and Meiping Sun, conclude that the region’s glaciers are particularly sensitive to climate change and the warming that has occurred over the past three decades. In “Glacier Change and Its Impact on Water Resources”, the researchers write that 11.7 percent of the total area of glaciers has been lost over that time. And with temperatures projected to increase over the next century by 1.2 degrees Celsius to 3.8, glacier loss is expected to accelerate rapidly.

The loss of glaciers in the region is limited in its impact on the region’s water resources (due to an increase in precipitation). Though the area now receives somewhat more rainfall than it did before, it still suffers because of the loss of glaciers. Glacier meltwater had been an important supplement to rainfall during the dry season, and also during years of below-normal rains, but it can no longer perform this role. Hydropower development is also limited because of the decline in meltwater. Paradoxically, the risk of floods has grown, because occasional pulses of meltwater course down streambeds. Other negative impacts include a higher risk of flooding.

Ultimately, the book does little to identify how changes in the region’s water resources will impact economic and social development in Xinjiang. This is particularly important, because this region—poised to experience economic and industrial development—will face increased demand for water resources at the same time that the supply of these resources will be threatened by glacier retreat.

You can find the chapter here.

In a small area of Nepal, it’s China that steps in to give aid
Villages in Nepal’s Upper Mustang are receiving support from an unlikely source: China. (Manfred Lentz/Flickr)

Encroaching on its neighbor, China has been building roads and providing grain to Nepal.

As most, if not all, Nepalese glaciers studied by scientists are shrinking, traditional ways of subsistence living has become increasingly difficult. With warming, lower snowfall and unpredictable weather patterns, the streams of glacial meltwater that supplies several Himalayan villages have disappeared.

For the past decade or so , harvest yields have been dwindling in some Upper Mustang villages due to an acute water shortage. Upper Mustang in northwestern Nepal is surrounded by Tibet to the west, east and north. The region’s main source of water, the Nhumina Himal glacier, is becoming unreliable as some meltwater streams have already dried up.

Today, instead of farming, the villagers wait for aid from China.

China provides rice, other grains, sugar and salt in aid. In recent years, most Upper Mustang villages have declined the help; they say that the aid products are very low quality. Only a few villages, out of desperation to survive, have to accept aid. Locals claim that their houses are inspected by Chinese officials to make sure that items they do not approve of, such as photos of the Dalai Lama, are taken down before they receive the aid.

The Samzong villagers, for example, mentioned that they disdain accepting aid from China. They think that China is using the aid to slowly gain control of the Nepal Himalayas, especially regions like Upper Mustang which were historically part of Tibetan Buddhist culture.

“What China is doing to us is exactly what China did to Tibet pre-1959,” said one 40-year-old woman. “They first come in, pretending to be nice by giving us grains. They pretend that they are building us roads for our welfare. These are all lies. Slowly but surely they are going to gain control of our land and subjugate us to oppression as they did to the Tibetans. The Nepali government is not going to defend us because they are accepting bribes from China too.”

The Chinese infrastructural influence is already present in Upper Mustang. Because there is no road from the low-lying Nepali districts to the district, most of the goods and services are brought from China, including motorcycles, soft drinks and chocolate. The Chinese are currently funding a road to connect Upper Mustang, expected to be complete by 2015.

The Nepali government’s development efforts have long been absent in this region. Last December, China announced that it will be increasing aid to Nepal with the condition that anti-China activities are removed and fleeing Tibetan refugees are returned to China. As nearby glaciers were used in 1960s-70s by the Tibetan Resistance Army as refuges from which they carried  out covert guerrilla actions against   Chinese army units, Upper Mustang is of special interest to China.

For those in Upper Mustang, fear comes from not just the melting glacial ice, but their neighbor to the north.