By Dipak Kurmi
Northeast India, with its lush hills and rugged terrain, braces each year for more than just the seasonal arrival of monsoon rains—it confronts a recurring and often devastating threat: landslides. While disasters like earthquakes and floods may capture greater public attention, landslides remain one of the most persistent and destructive natural hazards, particularly in mountainous and geologically fragile regions. Across the globe, thousands lose their lives annually, and the economic toll reaches billions of dollars, with rainfall-induced landslides being especially common in Southeast Asia. In India, around 15% of the total land area is susceptible to landslides, but it is the northeastern states that bear the brunt. Here, landslides have become a yearly ordeal during the June-to-September monsoon, disrupting lives, destroying infrastructure, and isolating communities in some of the country’s most remote and vulnerable regions.
Among the most affected sub-regions is the Barak Valley of Assam, whose isolation and geographical positioning render it particularly vulnerable. Over the past few years, the valley has repeatedly borne the brunt of landslide-triggered transportation paralysis and human tragedy. Monsoon-triggered landslides not only lead to deaths and destruction in the hilly terrain surrounding the valley but also sever the only vital arteries that connect this region to the Indian mainland—the NH 27 and the NF Railway broad gauge track passing through Dima Hasao, as well as the alternate NH 6 through the Jaintia Hills of Meghalaya. These lifelines traverse some of the most landslide-prone zones in the country, and their frequent disruption has now become a near-annual crisis.
The impact of these landslides extends well beyond the Barak Valley. States like Tripura, Mizoram, and parts of Manipur, all of which depend on these routes for the transportation of essential commodities, find themselves hostage to nature’s fury. This year has been no exception. Despite the monsoon not reaching its peak, the region has already experienced multiple breakdowns in connectivity due to landslides in the Dima Hasao corridor. NH 6 too has remained largely dysfunctional, rendering millions across Assam, Tripura, and Mizoram vulnerable to shortages of food, fuel, and medical supplies. With the onset of every monsoon, the same question resurfaces—why has this recurring crisis remained unsolved, even though these routes functioned seamlessly for decades? What has changed?
To answer this, one must examine the deeply embedded causal factors. At its core, a landslide is a manifestation of gravity acting upon loosened or unstable rock and soil, set into motion by external triggers. However, the susceptibility of any terrain to such movement is determined by a complex interplay of underlying geological, geomorphological, and climatic variables. In the context of Northeast India, several interlocking vulnerabilities have created a perfect storm.
Firstly, the region’s topography is inherently challenging. Steep slopes, unconsolidated soil, and a fragile geological foundation make it naturally predisposed to slope failure. The Dima Hasao district, through which both NH 27 and the railway line pass, is riddled with structurally weak lithologies—particularly shale interspersed with bands of kaolin, a clay mineral that notoriously expands when exposed to moisture. This geological composition is particularly treacherous. During rainfall, kaolin absorbs water and swells, exerting enormous pressure on slopes and tunnel walls, often culminating in massive slips.
This isn’t new knowledge. The challenges of constructing transport infrastructure in this terrain were noted as early as the late 19th century during the British colonial era. The then Chief Engineer of the Assam Bengal Railway observed in the District Gazetteer of Cachar: “Leaving the Cachar Plains, the (railway) line ran through shale of the worst description, often intermixed with bands of kaolin. The latter substance swells on exposure and causes heavy slips and exerts immense pressure on the sides of tunnels…” This prescient warning underscores how the geological realities have always posed formidable challenges to infrastructure development in the region.
Yet, despite such early warnings, there is little indication that modern engineering plans have adequately factored in these geological constraints. Road and railway alignments appear to have been undertaken without sufficiently detailed geotechnical investigations or high-resolution landslide susceptibility mapping. The result is a network that is perpetually vulnerable to collapse every monsoon season.
Compounding this vulnerability is the shifting nature of rainfall patterns. While seismicity is another known trigger of landslides in the region, it remains sporadic and unpredictable. Rainfall, on the other hand, is both recurring and increasingly erratic. The Indian Summer Monsoon (ISM) is the primary source of precipitation in this region, delivering heavy rains from June to September. Scientific studies across the globe have conclusively linked most rainfall-induced landslides to extreme precipitation events. In recent years, there has been a marked increase in the frequency and intensity of such events, a trend largely attributed to anthropogenic climate change. As global warming accelerates, so does the likelihood of sudden, high-intensity rainfall overwhelming natural drainage systems and slope stability.
This changing climate regime adds a layer of unpredictability that renders traditional rainfall threshold models inadequate. It becomes imperative, therefore, to establish region-specific rainfall-landslide relationships and determine precise localised thresholds under various geological and geomorphic conditions. Without this data, any early warning system would remain primitive at best.
Indeed, efforts at landslide risk reduction must be multi-pronged. There is no silver bullet. A robust, high-resolution geological and geotechnical study of the Dima Hasao and Jaintia Hills corridors is essential. This must be coupled with an assessment of slope stability, identification of existing faults and fracture zones, and real-time rainfall data monitoring. Geo-scientific data should guide engineering designs for roads, tunnels, and railways. Technologies like LiDAR, InSAR, and drone-based terrain mapping can play a transformative role in mapping vulnerable zones.
Yet, while the scientific community may point to solutions, implementation remains patchy. Bureaucratic inertia, funding constraints, and fragmented responsibilities between central and state agencies continue to delay critical interventions. The recurring landslides in Dima Hasao, which have now virtually cut off Barak Valley multiple times in a single monsoon season, are symptomatic of this administrative paralysis. Temporary repair and patchwork restoration—often hastily carried out without scientific reinforcement—only offer a short-lived reprieve. With the region being economically and strategically important, especially in light of India’s Act East Policy, this situation warrants urgent national attention.
The demand for an alternate route to Silchar and the Barak Valley has been raised several times, but such projects could take decades to materialise. In the interim, the only pragmatic option is to reinforce and climate-proof the existing corridors. This includes stabilising slopes, constructing adequate drainage systems, vegetation restoration, and ensuring that maintenance is continuous and pre-emptive rather than reactive. The development of an integrated Landslide Early Warning System (LEWS) for the region, similar to what the Geological Survey of India has piloted in some parts of the Western Ghats, could provide critical lead time for shutdowns and evacuations.
The human dimension of this crisis must not be ignored. For the millions residing in Barak Valley, Tripura, and Mizoram, the monsoon brings not just the hope of agricultural rejuvenation but the dread of prolonged isolation, price inflation, and even medical emergencies due to lack of access. Children miss school, businesses suffer losses, and emergency supplies dwindle. Landslides, in this context, are not just a geological phenomenon—they are a socio-economic disaster.
The landslide crisis in the Dima Hasao and Meghalaya corridors is a classic case of nature’s warnings being overlooked in the rush for development. While the terrain may be hostile and the monsoon increasingly erratic, the situation is far from hopeless. What is required is a paradigm shift—from short-term crisis management to long-term resilience building, from reactive repairs to proactive planning rooted in science. If the fragility of the Northeast’s terrain is matched with robust geotechnical engineering, informed governance, and climate-sensitive policies, the region can hope to navigate its monsoon seasons with far less peril. The crumbling corridors of connectivity can indeed be rebuilt—stronger, smarter, and safer.
(The writer can be reached at dipakkurmiglpltd@gmail.com)
