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NEW DELHI: On Tuesday afternoon, four earthquakes jolted Nepal in a span of just one hour, sending strong tremors across large parts of north India. A day later, the south Lhonak lake outburst in Sikkim triggered a flash flood in the Teesta river basin, leaving several dead.
Now, scientists are investigating whether the earthquake that occured a day earlier may have something to do with the flash flood in Sikkim.
According to a PTI report, the lake in Sikkim was already vulnerable and covered an area of 168 hectares.
Its area has now reduced to 60 hectares, indicating that about 100 hectares of water volume has breached the level, a senior official at the Central Water Commission (CWC) told PTI.
Notably, the official said that while it’s difficult to determine right now, a cloud burst does not cause such results.
The flood alerts were also shared with Bangladesh.
What happened in Sikkim?
According to reports, a cloudburst over the Lhonak lake triggered the torrential flooding in the valley located about 150 km (93 miles) north of Gangtok near the border with China.
The lake outburst also resulted in the breach of the Chungthang dam, which is the largest hydropower project in the state.
Satellite images released by the Hyderabad-based National Remote Sensing Centre showed that the area of south Lhonak lake reduced by over 100 hectares compared to its size on September 17.
This suggests that the lake outburst caused a flash flood in the Teesta River basin in north Sikkim.
At least eight people died and 69 more, including 22 Army personnel, are missing after the calamity.
The NRSC satellite imagery revealed that the lake covered approximately 162.7 hectares. Its area increased to 167.4 hectares on September 28 but drastically reduced to 60.3 hectares.
Cloudburst or earthquake?
According to the State Disaster Management Authority, the South Lhonak Lake suffered a phenomenon called glacial lake outburst flood (GLOF) in some portions, which caused a rapid rise in water levels with very high velocities downstream along the Teesta River Basin.
Glacial lakes, such as South Lhonak Lake, are substantial water bodies located in proximity to, on the surface of, or beneath a melting glacier.
Their increasing size poses heightened risks due to the fact that these lakes are often confined by precarious ice formations or sediment consisting of loose rocks and debris.
If the boundary surrounding them breaks, it can result in the rapid release of substantial volumes of water cascading down the mountainside, potentially leading to flooding downstream. This phenomenon is called GLOF.
Notably, GLOFs can also be triggered by earthquakes.
So far, officials estimate that the event may have been caused by heavy rainfall from a Bay of Bengal low-pressure depression.
But experts have not ruled out the possibility of an earthquake-like event triggering the disaster.
Some experts who have visited the site believe that the earthquake may have triggered the floods there.
(With inputs from PTI)
Watch Sikkim flash floods: 23 army men missing after cloud burst in Lachen Valley
Now, scientists are investigating whether the earthquake that occured a day earlier may have something to do with the flash flood in Sikkim.
According to a PTI report, the lake in Sikkim was already vulnerable and covered an area of 168 hectares.
Its area has now reduced to 60 hectares, indicating that about 100 hectares of water volume has breached the level, a senior official at the Central Water Commission (CWC) told PTI.
Notably, the official said that while it’s difficult to determine right now, a cloud burst does not cause such results.
The flood alerts were also shared with Bangladesh.
What happened in Sikkim?
According to reports, a cloudburst over the Lhonak lake triggered the torrential flooding in the valley located about 150 km (93 miles) north of Gangtok near the border with China.
The lake outburst also resulted in the breach of the Chungthang dam, which is the largest hydropower project in the state.
Satellite images released by the Hyderabad-based National Remote Sensing Centre showed that the area of south Lhonak lake reduced by over 100 hectares compared to its size on September 17.
This suggests that the lake outburst caused a flash flood in the Teesta River basin in north Sikkim.
At least eight people died and 69 more, including 22 Army personnel, are missing after the calamity.
The NRSC satellite imagery revealed that the lake covered approximately 162.7 hectares. Its area increased to 167.4 hectares on September 28 but drastically reduced to 60.3 hectares.
Cloudburst or earthquake?
According to the State Disaster Management Authority, the South Lhonak Lake suffered a phenomenon called glacial lake outburst flood (GLOF) in some portions, which caused a rapid rise in water levels with very high velocities downstream along the Teesta River Basin.
Glacial lakes, such as South Lhonak Lake, are substantial water bodies located in proximity to, on the surface of, or beneath a melting glacier.
Their increasing size poses heightened risks due to the fact that these lakes are often confined by precarious ice formations or sediment consisting of loose rocks and debris.
If the boundary surrounding them breaks, it can result in the rapid release of substantial volumes of water cascading down the mountainside, potentially leading to flooding downstream. This phenomenon is called GLOF.
Notably, GLOFs can also be triggered by earthquakes.
So far, officials estimate that the event may have been caused by heavy rainfall from a Bay of Bengal low-pressure depression.
But experts have not ruled out the possibility of an earthquake-like event triggering the disaster.
Some experts who have visited the site believe that the earthquake may have triggered the floods there.
(With inputs from PTI)
Watch Sikkim flash floods: 23 army men missing after cloud burst in Lachen Valley
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