Visions of Hell: martam

Wednesday, November 11, 2026

Sikkim: Two landslides and a subsidence area on NH10 between Rangpo and Gangtok

NH10 is the lifeline of Sikkim and of much of West Bengal’s Kalimpong district. Of the 114km of NH10 between Siliguri and Gangtok, roughly 90 km (between Sevoke–Gangtok) runs through mountainous terrain, and a large share of it hugs the Teesta river.
The highway is most vulnerable to landslides, rockfalls and subsidence between Coronation Bridge and Teesta Bazar. Here, erosion and subsidence have worsened since the construction of Teesta Low Dam Projects III (27th Mile, near Rambi) and IV (Kalijhora), which local stakeholders blame for siltation and altered river behaviour. The October 2023 GLOF from South Lhonak Lake added new hazards along the Teesta corridor.

Though the Teesta Bazar–Gangtok section is generally more stable, it has its own nightmare zones. The 20th Mile landslide at Bardang, between Singtam and Rangpo, has recently caused repeated closures of NH10 but the Martam landslide, once a major trouble spot, appears to have stabilized through engineering treatment and natural consolidation working in tandem.

Martam landslide (27°15’34.4’’N,88°33’02.2’’E)
The Martam landslide located approx 9km from Ranipool towards Singtam was a very trouble some slope failure which affected transportation and the lives of people for years. It was a very active and large (190mX75m) landslide which seems to have now healed thanks to a combination of technology and nature.

Google Earth Images of the Martam landslide of 2022 and 2025 which show a less active landslide in the image below.

My images of 2019 and Oct 2026 show that the Martam landslide has indeed become more stable.

A technical study on the Martam landslide is available here:
(IOSR Journal of Applied Geology and Geophysics (IOSR-JAGG) e-ISSN: 2321–0990, p-ISSN: 2321–0982.Volume 11, Issue 4 Ser. I (July. – Aug. 2023), 52-56 www.iosrjournals.org).

The 'forever' sinking area near Martam (27.252609N 88.5641663E)

This area of subsidence on NH10, a short distance towards Singtam from Martam (see Google Earth satellite image of 2025 above) has been there for a long, long time and as the photos below show nothing much has changed over the years.

The 20th Mile Landslide at Bardang (27.206257N 88.489384E)
20th MIle landslide at Bardang on 16Oct2026

The Bardang area near Singtam in Sikkim has long been an area of slope instability and has disrupted traffic and caused economic losses to Sikkim during the annual monsoon seasons for decades. The initial trigger of the landslide appears to be natural with heavy rain and geology being the primary causes.
In 2010, the Border Roads Organization constructed an 80m long, cut and cover tunnel at Bardang as a short term measure to allow safe passage to those using the roadway, rather than stabilizing the the slope. However, the landslide area has progressively expanded up the hillside and the existing protection has been overwhelmed by the sheer volume of debris (see above photo of 16Oct2026).
In the monsoons of 2026, the NH10 (Sikkim section) was crippled by multi-day closures and traffic restrictions stretching over four months (June to October 2026) with traffic being diverted thru alternate routes.