Glacial lakes a threat to villages, says expert
ISLAMABAD, Feb 24: With the summer approaching, the Pakistan Meteorological Department (PMD) is concerned about more than 50 potentially hazardous lakes formed in glaciers in the northern areas.
Most of these lakes can bring disaster for small settlements downhill.
“Glacial lake outburst floods (Glof) have become a concern. Glofs are a fairly unique phenomenon where huge lakes are formed (or water is dammed) inside the walls of glaciers. They are particularly dangerous because the walls holding the massive water bodies can break due to intense heat or torrential rains causing flooding,” said Dr Ghulam Rasul, the chief meteorologist at the PMD.
The floods could cause devastations, especially to small villages that lay directly in their paths in some cases.
“Last year, we installed four automatic weather stations on Passu and the Baltoro glaciers in Gilgit-Baltistan to better understand the melting rates of glaciers in the area. The department has been recording constant rise in temperatures in the region,” said Dr Rasul.
According to the PMD, temperatures in the northern areas have increased by 0.8 and 1.5 degrees centigrade between 1990 and 2010.
The chief meteorologist said because of the rising temperatures, the phenomenon of glacial lake outburst floods was becoming a regular feature in the summers in the northern areas. His department has recorded five Glof events in the last two years.
“The Buni glacier last year caused extensive damage to houses in its path. About two to three Glof events are now permanent features at the Gulkin glacier on the Karakorum Highway and that now feeds the Attabad Lake in Hunza,” said Dr Rasul, explaining how another glacial lake outburst flood in 2008 in the northern areas destroyed over 50 out of the 135 houses.
Not only the Glof events but also the fast retreating glaciers are a disturbing factor.
Another expert on weather monitoring in PMD explained how the Passu glacier had retreated over 20 metres in the last 15 years.
“The weather is becoming unpredictable. More worrying than retreating glaciers are our findings on how the Passu and Baltoro glaciers are thinning,” said the senior official in the PMD. Explaining the reasons, the expert said, “The ice mass of the Baltoro glacier has reduced because most of the low lying tributaries have disappeared and others are retreating fast. The low lying tributaries like the Liligo glacier and the Silili glacier, which once fed the Baltoro, are already disconnected from it. And the Payo glacier, which was another important tributary of the Baltoro glacier, has completely disappeared.”
To help understand the changing climate over Gilgit-Baltistan better, the PMD has got 14 new automatic weather stations to expand its glacier monitoring network to study the rapidly melting glaciers into the higher Himalayas and the Karakorum ranges.
The monitoring units, each costing $45,000, were obtained in grant from Finland under the glacial lake outburst floods (GLOF) programme.
It would help better assess impacts of warming weather in the upper Indus basin and related flood hazards.
Pakistan’s vast glacial area covers around 15, 000 square kilometres which is rapidly retreating.
The new stations (installed above 4,000 metres) would help gather data on temperature, humidity, precipitation, pressure, solar radiation and wind speed and direction.
So far, Pakistan has been relying on images from Chinese and Japanese remote sensing satellites to study glaciers.
Although satellites offer inputs from inaccessible terrains, the data sometimes did not match ground observations.
The new weather monitoring system would help real-time measurements from the ground, said Dr Rasul, elaborating how the stations would also help predict possible glacial floods and avalanches just in time to warn and even evacuate settlements in the paths of the sudden floods.