Three dead and two missing following flash flood in Arunachal Pradesh.

Three people have been confirmed dead and another two are missing following a flash flood in the Keyi Panyor District of Arunachal Pradesh State, India, on Wednesday 24 June 2026. A further 54 families have been displaced by the incident, in which waters from the Rangandani River Dam Lake over-topped a wall surrounding a residential camp for employees of the North Eastern Electric Power Corporation working on the Panyor Lower Hydroelectric Project (also known as the Rangandani Dam), following days of heavy rain associated with the Summer Monsoon. 

Damage caused by a flash flood which swept through a residential block for workers at a hydroelectric dam in Arunachal Pradesh, India, on 24 June 2026. ANI.

About thirty houses were destroyed at the dam workers colony, with another ten houses destroyed and fourteen damaged in related incidents in neighbouring communities, which have also been hit by flooding and landslide events caused by heavy rains in the area. Landslides are a common problem after severe weather, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. Several major roads in the area have also been damaged, and the heavy rains are making air transport difficult, hampering the efforts of rescue workers.

Arunchal Pradesh has a monsoon season that begins around the end of April or beginning of May and ends around September, bringing 2-4000 mm of rain to the region each year. In the twenty four hours prior to the incident, 74 mm of rainfall had fallen in the area, which is high, but should not have been sufficient to cause flooding at a camp with flood defences on a dam lake where the water level can be controlled to some extent by releasing water from the dam. This has led to speculation that an earlier incident, such as a landslide, may have temporarily blocked the flow of the river upstream of the dam lake, and that when this temporary blockage failed, a large amount of water surged downstream overcoming the colony's flood defences.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate. 

Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

This situation is particularly intense in South Asia, due to the presence of the Himalayas. High mountain ranges tend to force winds hitting them upwards, which amplifies the South Asian Summer Monsoon, with higher winds leading to more upward air movement, thus drawing in further air from the sea. However, despite the incidents in Arunachal Pradesh this week, the Indian Monsoon is predicted to be be week this year, due to a developing el Niño system over the southern Pacific Ocean, leading to concerns that the country could suffer widespread droughts and famine this year.

The el Niño is the warm phase of a long-term climatic oscillation affecting the southern Pacific, which can influence the climate around the world. The onset of el Niño conditions is marked by a sharp rise in temperature and pressure over the southern Indian Ocean, which then moves eastward over the southern Pacific. This pulls rainfall with it, leading to higher rainfall over the Pacific and lower rainfall over South Asia. This reduced rainfall during the already hot and dry summer leads to soaring temperatures in southern Asia, followed by a rise in rainfall that often causes flooding in the Americas and sometimes Africa. Worryingly climatic predictions for the next century suggest that global warming could lead to more frequent and severe el Niño conditions, extreme weather conditions a common occurrence.

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Trachischium apteii: A new species of Worm-eating Snake from Arunachal Pradesh, India.

Members of the Natricid Snake genus Trachischium are commonly known as Slender Snakes or Worm-eating Snakes. They are fossorial in nature (live underground in burrows) and are distributed in montane ranges of India, Nepal, Bhutan, China, Myanmar, and Bangladesh. The genus currently contains six species: Trachischium fuscum, Trachischium guentheri, Trachischium laeve, Trachischium monticola, Trachischium sushantai, and Trachischium tenuiceps. The Snakes of this genus are poorly studied, likely due to their fossorial nature; however, these are common elements of high-elevation herpetofaunal assemblages.

In a paper published in the journal Comptes Rendes Biologies on 19 November 2019, Harshal Bhosale of the Bombay Natural History Society,  Gaurang Gowande of the Department of Biotechnology at Fergusson College, and the Annasaheb Kulkarni Department of Biodiversity at Abasaheb Garware College, and Zeeshan Mirza of the National Centre for Biological Sciences at the Tata Institute of Fundamental Research, describe a new species of Trachischium from Arunachal Pradesh State in India.

In the course of a herpetological investigation, Bhosale et al. visited Talle Valley Wildlife Sanctuary in Arunachal Pradesh, northeastern India, and collected three specimens of a Trachischium species that resembled Trachischium monticola in bearing 15 dorsal scale rows, but did differed from it in some aspects, primarily their colouration. In order to ascertain the identity of the specimens from Talle Valley, type material of Trachischium in the collection of the Natural History Museum in London, as well as non-type material in the collection of Bombay Natural History Society in Mumbai were examined. Based on our observations, the specimens from Talle valley appear to be a form that is distinct from Trachischium monticola and other congeners, and is therefore described as a new species.

The new species is named Trachischium apteii, in honour of Deepak Apte, the Director of the Bombay Natural History Society, a marine biologist and conservationist, for his contribution to conservation, and for his continued support to Harshal Bhosale and to the Arunachal Expedition, which led to the discovery of the new species.

The species was found during an expedition to Arunachal Pradesh which ran from 25 June 2019 to 5 August 2019, along with other members of the genus. The study was conducted under permits issued by the Forest Department of Arunachal Pradesh. Three specimens of the new genus were collected in the field by hand, were photographed, and later two specimens were euthanized within 24 hours of capture. The other specimen was released after recording scalation and other morphometric data and clipping a single scale for molecular work. The Snakes were found under logs during a daytime search. The individuals were likely seeking refuge under the logs during the day. Locals informed the scientific team that the Snakes have also been found while digging during non-monsoon seasons.

Trachischium apteii, holotype female specimen, BNHS 3550, in life. Bhosale et al. (2019).

Trachischium apteii  is a large-sized member of the genus, with the female specimen collected having a total length of 331 mm. The tail comprises 11-13% of the total length. Dorsal scales smooth and glossy, arranged in 15 rows throughout the body. The Snakes are dark brown to black with faint dorsal longitudinal lines, lacking yellow patch on the neck and the belly being yellowish.

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Cuon alpinus: Understanding the distribution of Dholes in northeast India.

The Dhole, or Asian Wild Dog, Cuon alpinus, is an Endangered social carnivore found in forested landscapes of South and Southeast Asia. Historically widespread across Asia, the species’ range has contracted by about 80%. The current distribution extends across most of South and Southeast Asia and parts of China but is largely restricted to protected areas. The protected forest landscapes south of the River Ganges in India are a stronghold for the species, with the largest Dhole population. However, the species has undergone local extirpation across parts of its former range as a result of declines of prey species, loss of habitat and, potentially, disease. Information on Dholes in northeast India in particular is limited, despite the fact that this landscape shares continuous forest with Myanmar and Southeast Asia, forming an important part of the species' global range.

A Dhole, or Asian Wild Dog, Cuon alpinus. David Raju/Wikimedia Commons.

In a paper published in the journal Orynx on 23 October 2019, Priya Singh of Researchers for Wildlife Conservation at the National Centre for Biological Sciences, and the School of Natural Resources and Environment at the University of Florida, Arjun Srivastha of the Department of Wildlife Ecology and Conservation at the University of Florida, and David Macdonald of the Wildlife Conservation Research Unit at the University of Oxford, provide a compilation of dhole presence records from across northeast India using data extracted from multiple sources.

Current knowledge of Dholes in north-east India is restricted to landscapes north of the River Brahmaputra. This is primarily because of the paucity of baseline ecological data from the region, given its undulating terrain, difficulty of access, wet climatic conditions, and socio-political insurgencies.

Using data from camera-trap surveys Singh et al. examine factors influencing fine-scale site-use by Dholes in Dampa Tiger Reserve in Mizoram State. They discuss the implications of their results for Dhole conservation in northeast India, where the focus of wildlife managers is directed mainly towards population recoveries of and local recolonisation by the Tiger, Panthera tigris. They further provide recommendations for management interventions that could facilitate conservation of Dholes in this hitherto neglected landscape.

Dampa Tiger Reserve lies in the Indo-Myanmar Biodiversity Hotspot. The reserve is contiguous with the Chittagong Hill Tract region of Bangladesh to the west. The core area of the Reserve covers 500 km², and the multi-use buffer covers an area of 488 km². The Lushai Hills traverse the reserve, with altitudes of 250-1100 m. Mean annual rainfall is 2000-2500 mm. The Reserve supports a high diversity of Carnivores, including, in addition to the Dhole, four species of Felids and two species of Ursids. In the course of the study Singh et al. also recorded the Elephant, Elephas maximus, Gaur, Bos gaurus, Sambar, Rusa unicolor, Red Serow, Capricornis rubidus, Muntjac, Muntiacus muntjak, and Wild Pig, Sus scrofa.

Northeast India, with the Dampa Tiger Reserve in Mizoram and locations where the Dhole, Cuon alpinus, has been recorded, with corresponding reliability scores. Singh et al. (2019).

Singh et al. compiled Dhole presence records for nine northeastern states: Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, Tripura, and West Bengal. They searched for records from 1990 onwards in newspaper reports, scientific articles, grey literature (including species checklists), and reports by Forest Department personnel, local informants and naturalists working in the region. For each record they noted the type of evidence (direct/indirect), the date of the sighting, the administrative status of location (protected/non-protected), and the source person or reference. They assigned reliability scores for each record, from 1 to 5, with 1 being most reliable, and 5 least reliable.

From December 2014 to March 2015, Singh et al. deployed 79 pairs of Cuddeback Ambush IR camera traps across 80 km² in the northeast of Dampa Tiger Reserve’s core area. At each station they placed two cameras facing each other, about 30 cm above the ground, on either side of forest trails or on riverbeds. Mean inter-trap distance was 1.02 km, with traps remaining active for an average of 64 days. Although the stations were intended to photograph wild Felids, they also photographed other Carnivores. Dholes generally use forest trails and riverbeds for movement, marking territories and hunting, and our sampling design therefore incorporated areas used by the species.

Singh et al. obtained presence records from 80 locations for 1990-2018, of which we considered 41 records from 2010–2018 with reliability scores of 1-3. In the case of multiple records for the same site, they considered the most recent record with the highest reliability score. Most records were from Arunachal Pradesh (14) and Assam (8), with five records from Mizoram and Nagaland, four from West Bengal, three from Meghalaya and two from Sikkim. There were no recent records of Dholes from Manipur and Tripura. A total of 5033 camera trap-days in Dampa Tiger Reserve generated 500 photoencounters of Dholes, comprising 92 detections (one per 24 hour duration) across 33 sites. 

Singh et al. found photo-capture frequencies of key prey species: Sambar (236), Muntjac (145), Wild Pig (92); to be positive influences, as were the distance to reserve boundary, and photo-capture frequencies of Forest Department personnel, while photo-capture frequencies of other humans were  negative influences on site-use by Dholes.

There are records of Dholes across several areas of northeast India, including in unprotected areas. Previous global assessments indicated that the species faced near or complete local extirpation to the south of the River Brahmaputra, something refuted by Sigh et al.'s findings from Dampa Tiger Reserve. Corroborating current knowledge from other landscapes, showed a positive relationship between Dhole site-use and Sambar presence. Across their extant distribution, the range of Dholes overlaps with that of Tigers and Leopards, Panthera pardus. Wildlife managers in this region and elsewhere subscribe to unsubstantiated notions that dhole presence impedes colonisation by Tigers, and consequently treat Dholes as a problem species. On the contrary, Tigers, Leopards and Dholes can co-exist provided protected areas support adequate densities of medium- to large-sized prey species.

Dampa Tiger Reserve is an important refuge for Dholes in northeast India. It supports large tracts of inviolate protected spaces, and habitat connectivity with forested landscapes of the Chittagong Hill Tract region to the west, Mamit Forest Division to the north and Thorangtlang Wildlife Sanctuary to the south. Singh et al's camera-trap data indicate the presence of a guild of large herbivores in the Reserve, with at least five prey species of medium and large ungulate herbivores, facilitating the long-term persistence of dholes there. The findings re-emphasise the importance of protected areas, which can serve as source sites for sustaining Dhole populations across the region.

In areas with low prey densities, carnivores may have significant dependence on livestock, and are consequently stigmatised. There is a strong negative relationship between Dholes and livestock owners in Arunachal Pradesh and other locations in the region. Given that Dholes also occur outside protected areas in this region, they are potentially vulnerable to retributory killing. Negative interactions between people and Dholes necessitate interventions to reduce poaching and facilitate recovery of prey, especially for species such as Sambar that are impacted by low recovery rates following prolonged poaching. Singh et al.'s findings need to be augmented with a systematic survey across the locations they identified, specifically in the states of Mizoram and Nagaland, to facilitate a pan-northeast India strategy for Dhole conservation.

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Magnitude 5.5 Earthquake in Arunachal Pradesh, India.

The United States Geological Survey recorded a Magnitude 5.5 Earthquake at a depth of 16.8 km about 64 km to the north of the town of Bomdila in West Kameng District, Arunachal Pradesh, India, slightly after 2.50 pm local time (slightly after 9.20 am GMT) on Friday 19 April 2019. The event was felt across northeastern India, as well as in eastern Bhutan, though there are no reports of any damage or casualties. 

The approximate location of the 19 July 2019 Arunachal Pradesh Earthquake. USGS.

Earthquake activity in the area is caused by the uplift of the Tibetan Plateau, due to the impact of India into Eurasia to the south. he Indian Plate is moving northwards at a rate of 5 cm per year, causing it to impact into Eurasia, which is also moving northward, but only at a rate of 2 cm per year. The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

 

 Block diagram showing how the impact of the Indian Plate into Eurasia is causing uplift on the Tibetan Plateau. Jayne Doucette/Woods Hole Oceanographic Institution.

 

Much of northern India and neighbouring areas of Central Asia and the Himalayas, are prone to Earthquakes caused by the impact of the Indian Plate into Eurasia from the south. When two tectonic plates collide in this way and one or both are oceanic then one will be subducted beneath the other (if one of the plates is continental then the other will be subducted), but if both plates are continental then subduction will not fully occur, but instead the plates will crumple, leading to folding and uplift (and quite a lot of Earthquakes). The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

 

The movement of India into Eurasia over the last 71 million years. USGS.

 

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

 

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Landslide injures two in Arunachal Pradesh, India.

Two people have been injured following a major landslide that hit the NH-415 highway between Itanagar and Naharlagun at about 5.45 am local time on Wednesday 17 July 2019. Local authorities initially feared the number of people involved would be far higher, due to a large number of vehicles buried beneath mud and rock at the site, though it subsequently emerged that the majority of these were vehicles parked by the road, many of them associated with a local car dealership. Both of the injured persons are being treated at the Ramakrishna Mission Hospital in Itanagar.

Vehicles hit by a landslide in Arunachal Pradesh, India, on 17 July 2019. EastMojo.

The incident is the latest in a series of such events in the state associated with heavy rains caused by the summer monsoon. Landslides are a common problem after severe weather, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. Arunchal Pradesh has a monsoon season that begins around the end of April or beginning of May and ends around September, bringing 2-4000 mm of rain to the region each year.

 

Autorickshaw hit by a landslide in Arunachal Pradesh, India, on 17 July 2019. EastMojo.

 

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate. This situation is particularly intense in South Asia, due to the presence of the Himalayas. High mountain ranges tend to force winds hitting them upwards, which amplifies the South Asian Summer Monsoon, with higher winds leading to more upward air movement, thus drawing in further air from the sea.  

 

 Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

 

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Magnitude 5.9 Earthquake in Arunachal Pradesh, India.

The United States Geological Survey recorded a Magnitude 5.9 Earthquake at a depth of 14 km about 33 km to the north of the town of Aalo in West Siang District, Arunachal Pradesh, India, at about 1.45 am local time on Wednesday 24 April 2019 (about 8.15 pm on Tuesday 23 April GMT); the same Earthquake was measured by the China Seismological Network as a Magnitude 6.3 event at a depth of 10 km in Medong County, Tibet, which occured at a 4.15 am local time (this difference is caused by China and India both having a single standard time zone, with the effect that the focal points detected by the two agencies, while only a few km apart, are in time zones with a difference of three hours). The event was felt across northeastern India, as well as in China, Myanmar, Bangladesh, Bhutan, and Nepal, though there are no reports of any damage or casualties. 

The approximate location of the 6 December 2017 Tibet Earthquake. USGS.

Earthquake activity in the area is caused by the uplift of the Tibetan Plateau, due to the impact of India into Eurasia to the south. he Indian Plate is moving northwards at a rate of 5 cm per year, causing it to impact into Eurasia, which is also moving northward, but only at a rate of 2 cm per year. The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

 Block diagram showing how the impact of the Indian Plate into Eurasia is causing uplift on the Tibetan Plateau. Jayne Doucette/Woods Hole Oceanographic Institution.

Much of northern India and neighbouring areas of Central Asia and the Himalayas, are prone to Earthquakes caused by the impact of the Indian Plate into Eurasia from the south. When two tectonic plates collide in this way and one or both are oceanic then one will be subducted beneath the other (if one of the plates is continental then the other will be subducted), but if both plates are continental then subduction will not fully occur, but instead the plates will crumple, leading to folding and uplift (and quite a lot of Earthquakes). The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

 The movement of India into Eurasia over the last 71 million years. USGS.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

 

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