Heavy Rains, Steep Slopes And Tough Terrain: Why Sikkim Is Prone To Landslides

News18

2 days ago

Last Updated:
Sikkim, susceptible to heavy monsoon rains, has experienced several deadly floods and landslides in recent years.
A devastating landslide hit an Army camp in Lachen, Sikkim, on Sunday, claiming the lives of at least three Army personnel and leaving six security personnel, including combatants, missing.
Sikkim and other northeastern states have been battling heavy rains, floods, and landslides since Sunday. Over 1,500 tourists were stranded due to these conditions. Numerous videos on social media depicted the aftermath of a cloudburst in the state on the night of May 30 and 31.
The heavy rains in parts of Sikkim have caused extensive damage to roads and bridges, with the Teesta River dangerously overflowing. On Monday, the Tourism and Civil Aviation Department of Sikkim announced the restoration of the Chungthang-Phidang road in Mangan district, allowing the safe evacuation of stranded tourists to begin.
Floods and Landslides in Sikkim Between 2023 and 2025
Sikkim, susceptible to heavy monsoon rains, has experienced several deadly floods and landslides in recent years.
In August 2024, a massive landslide damaged HPC's Teesta V Hydropower Station, causing significant infrastructural damage, though casualty figures were not reported. In July 2024, a 40-year-old woman died when her vehicle was hit by large boulders near Sisney. This landslide led to the closure of National Highway 10, temporarily isolating the state.
In October 2023, a cloudburst caused the South Lhonak Lake to overflow, resulting in a catastrophic flood. The Teesta III Dam was destroyed, 15 bridges were swept away, at least 10 people died, and 82 went missing, including 22 Army personnel.
In August 2023, a 4-year-old child died when a landslide destroyed their home. Continuous rainfall during this period led to multiple landslides in the region. In July 2023, a 40-year-old man was killed in a landslide that damaged several houses in Lingzya village, triggered by heavy rains.
With the Himalayas in North India drawing large crowds, tourists have increasingly turned to Sikkim for its majestic Himalayan views. The state's remote areas often remain disconnected from the mainland due to inadequate infrastructure, leading to more urbanization, road construction, hydropower projects, and urban expansion involving large-scale hill cutting and deforestation. These activities weaken slope integrity.
In addition to man-made factors, Sikkim is geologically part of the young and fragile Himalayan mountain system. The rocks in this region are relatively weak and fractured, making them more prone to slope failure. Unlike the western Himalayas, the eastern Himalayas are more tectonically active, experiencing frequent earthquakes and tremors that destabilize the terrain.
Topographically, Sikkim's landscape is characterized by extremely steep slopes and narrow valleys, making the region more vulnerable to landslides, especially during periods of intense rainfall. An official release on Monday mentioned, 'Rescue teams are relentlessly working around the clock under extremely challenging terrain and adverse weather conditions to locate and rescue the six personnel who remain missing."
The state is also known for receiving heavy and concentrated monsoon rains, often exceeding 3,000 mm annually, which quickly saturate the soil and trigger landslides.
Sikkim is also home to several glacial lakes that are growing due to melting glaciers. These lakes pose a risk of Glacial Lake Outburst Floods (GLOFs), which can trigger massive landslides downstream.
With the Teesta River swelling and causing massive devastation in the state, and ongoing rainfall, authorities have issued advisories urging residents and tourists to exercise caution and avoid high-risk areas. Emergency services are on high alert, and relief camps have been set up to accommodate displaced families.