Showing posts with label Monsoons. Show all posts
Showing posts with label Monsoons. Show all posts

Saturday, 18 July 2026

At least eight dead following landslide in Chongqing, China.

Eight people are known to have died and thirty four people are missing following a landslide in Pengshui County in the Chongqing Municipality of China on Friday 17 July 2026. The incident took place at about 9.10 am local time, and caused about 18 000 m³ of rock and soil (including boulders up to 3000 m³) to shift, burying ten residential buildings. Around 1100 people have been evacuated from the area around the incident, with water, electricity, and gas supplies cut off from buildings within 1 km of the landslide as a precaution. Around 800 rescue workers have been deployed to the site, with ten people dug out of the rubble so far, two of whom are described as being in a serious condition in hospital.

The scene of a landslide which killed at least eight people in Chongqing, China, on 17 July 2026. AFP.

The incident happened during heavy rains associated with the summer monsoon, with 192 mm of rain falling overnight before the landslide. Landslides are a common problem after severe weather events, 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. 

However, local authorities have also noted that the area where the landslide occurred is noted for its 'unpredictable' geology, with the Wujiang River cutting through uplifted an karst (eroded limestone) terrain with steep-sided valleys and many cliffs prone to major rockfalls. 

Rescue workers surveying the site of the 17 July 2026 Chongqing landslide from a nearby bridge. Andy Wong/Associated Press.

Chongqing has a subtropical climate with a rainy season running from mid April to mid October, though rain falls year round. Rainfall is typically highest in June when the area often receives over 200 mm of rainfall. July is drier, but typically still has over 180 mm of rain. Prior to Human settlement, the area was largely covered by forests, with a cool temperate deciduous forest during the last Pleistocene glaciation being replaced by a broad-leafed evergreen forest in the Holocene. However, Chongquing is now one of the most densely populated areas of China, which has led to the loss of much of this forest, the roots of which would have helped to bind soils on steep-sided slopes, leaving areas such as the Wujiang River valleys exposed to heightened landslide risks, and often heavily populated.

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Wednesday, 8 July 2026

Three dead and five missing following landslide at construction site in Kerala.

Three people have died and another five are missing following a landslide at a construction site in Wayanad District, Kerala, at about 1.00 pm local time on Tuesday 7 July 2026. The three dead men have been identified as labourers Anmol Gorai from Jharkhand, Vikas Kumar Singh from Bihar and Chandrabhan Pal from Madhya Pradesh. The incident happened amid heavy rainfall associated with the summer monsoon, which appears to have triggered the collapse of a large pile of earth produced by the construction of a road tunnel intended to connect the town of Meppadi in Wayanad District to the village of Anakkampoyil in the neighbouring Kozhikode District. 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.

An ongoing rescue operation at the site of a landslide in Kerala State, India. Press Trust of India.

The landslide swept across the construction site, over a nearby road where it swept several vehicles away, then over a temporary labour camp for workers at the site, then a local church and house. All work at the site, other than searching for the missing persons, has stopped pending an investigation into the incident.

Managers at the site, which is being operated by Dilip Buildcon Limited, have claimed that the landslide started on land above the construction site, and was therefore not their fault. However, local authorities have observed that the company appears to have been in breach of at least two directives issued to by the Kerala Public Works Department, one of which was to remove the spoil heap, which was perceived as dangerously large, while the other was not to allow work on the site to be carried out on the site during heavy rainfall, due to the possibility of landslides.

CCTV footage of the landslide sweeping vehicles from a road. India Today.

The tunnel project was approved in 2020, and is intended to relieve pressure on the Thamarassery Ghat Road, which is prone to closures due to landslides during the monsoon season. However, from the outset it has been opposed by environmental groups in Kerala, who were worried that it would affect areas which form a key part of the Western Ghats Biodiversity Hotspot, in particular forests used by wild Elephants, and that there was a danger of tunnelling activities making the hillsides more prone to landslides.

A bus swept into a ravine by the 7 July 2026 Wayanad landslide. Press Trust of India.

These concerns form part of a wider dispute between the Indian Government, which considers large infrastructure projects to be a vital part of its mission to raise millions of Indian citizens out of poverty, and environmentalists, who consider many of these projects to be poorly thought out, and not to take into account the special environmental needs of places such the Western Ghats, nor the current or projected future climate of the region. While such objections are often depicted by India's politicians as being anti-development sentiments which will condemn future generations to poverty, environmentalists worry that large projects which do not take into account the environment and climate risk failure, leaving the areas affected without any meaningful improvement to infrastructure and potentially significant environmental degradation, leaving local communities worse off than they are now.

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.

Kerala has a complex seasonal cycle, driven by the presence of the Western Ghats mountain range, which largely block the dry northerly winds which dominate the climate of much of India, and its proximity to the equator, which leads to a double monsoon system. Such a double Monsoon Season is common close to the equator, where the Sun is highest overhead around the equinoxes and lowest on the horizons around the solstices, making the solstices the coolest part of the year and the equinoxes the hottest. In Kerala this results in a Southwest Monsoon, which lasts from May to September, and is driven by winds from the southern Arabian Sea dumping water onto the Western Ghats, followed by a Northwest Monsoon, which lasts from October to December, where winds from the Bay of Bengal do the same. Of the two monsoons, the southwest is the wetter, due to the proximity of the sea, with June typically being the wettest month, with an average of 341 mm of rain falling in the month.

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Sunday, 28 June 2026

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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Monday, 26 January 2026

Thirty four confirmed dead and many more still missing following landslide in West Java.

Thirty four people have been confirmed dead and 56 are still missing following a landslide which hit the village of Pasirlangu on the side of Mount Burangrang in West Java Province, Indonesia, on Saturday 24 January 2026. As well as local villagers, the landslide is reported to have hit a group of Indonesian marines on a training exercise in the area, who are thought to have been wiped out. So far the bodies of four marines have been recovered, with another nine still missing. 

A rescue team searching the site of a landslide which hit the village of Pasirlangu in West Java on 24 January 2026. Septianjar Muharam/Xinhua.

The landslide is reported to have been triggered by heavy rains associated with the northeast monsoon. Landslides are a common problem after severe weather events, 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. However, the root cause of the landslide appears to have been deforestation, with a large area of forest above the village cleared to create space for commercial vegetable farming. This process removes the root structure which binds soil together, making slopes more vulnerable to slippage, particularly in areas such as West Java, where soils tend to be volcanic, as such soils typically have much smaller particle sizes and lose cohesion more rapidly when they become waterlogged.

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 seasons, 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.

Java has two distinct Monsoon Seasons, with a Northeast Monsoon driven by winds from the South China Sea that lasts from November to February and a Southwest Monsoon driven by winds from the southern Indian Ocean from March to October. Such a double Monsoon Season is common close to the equator, where the Sun is highest overhead around the equinoxes and lowest on the horizons around the solstices, making the solstices the coolest part of the year and the equinoxes the hottest.

The winds that drive the Northeast and Southwest Monsoons in Southeast Asia. Mynewshub.

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