Tragedies like the Wayanad landslides repeat themselves partly because their lessons are not brought to bear on our understanding of the local amplifiers of extreme events. A view of a mountain of the Western Ghats in Wayanad, Kerala, November 15, 2022.
| Photo Credit: Nakkeeran Raveendran/Unsplash

At no place on the earth is the climate risk zero — yet when natural hazards strike, the resulting loss of lives, livelihoods, and assets sting. Disaster management and recovery play a crucial role in alleviating the pain. Unfortunately, however, a blame game may follow asking whether early warnings could have averted the tragedy.

Any early warning that may have been issued will always start with the weather forecast for the area where the hazard manifested. Proactively mitigating disasters instead of always managing them after they happen requires climate risk outlooks that go out to a decade or longer.

Further, post-facto analyses of deadly disasters — like the landslides in Wayanad, Kerala, on July 30 — often do not appreciate the fact that broad warnings of risks can hardly be translated to specific actions. For example, if we declare the entire Western Ghats to be vulnerable to landslides, governments can develop and enforce regulations to protect the whole range from deforestation, development, monoculture plantations, etc.

However, doing so will mitigate some landslides; it won’t get rid of extreme events induced by climate change anytime soon. Some landslides will occur anyway even if the Ghats enjoy the fullest protections from human perturbations because the risk is never zero.

Predictions for disaster management, mitigation

Similarly, the predictions of models will also always be imperfect. If we are to improve their ability to predict extreme events more accurately (in terms of their location and amplitude), we need to fully understand the effects of local drivers that could exacerbate the climate’s effects. After every extreme event, someone claims global warming is a contributor — yet the relationship between local events and global warming complicates the truth of such claims.

The drivers of climate extremes originate from a far-away place but are usually exacerbated by some regional, location-specific factors.

For instance, a 2015 study (which included this author) indicated that coastal sea surface temperatures have a strong influence on heavy rain along India’s west coast. Wayanad district lies about 80 km from this coast. Monsoon winds stream across the equator and continue to load up on moisture as they turn southwesterly and head towards the Western Ghats. As they approach the coast, the winds sense they will have to climb the Western Ghats and slow down. Slower winds reduce the evaporation over the coastal ocean and the coastal waters tend to warm up — and warm waters exert a strong control on the atmosphere and rainfall.

Such a warming is typically seen up to 10 days ahead of a heavy rain event over the coastal ocean. Global models typically miss such local, small-scale warming or cooling processes and tend to underestimate the amount of rain in an extreme event. Enhancing the coastal observations and assimilating them into forecast models is expected to improve predictions.

This is also why adopting location-specific measures like legal protections for biodiversity can help mitigate disasters. Governments can also bolster their regulatory strategies using predictions of the climate up to a decade in the future and combining each prediction with hyperlocal risks.

Similarly, national and local governments will have to work together and share monitoring, reporting, and verification responsibilities to mitigate risk. Finally, all these consequences of the relationship between global warming and local events will have to be accounted for in budgetary provisions. Otherwise, mitigating disasters may not be sustainable.

Further, predictions with a lead time of a few weeks could help disaster management personnel mobilise towards locales with the highest imminent risk and avoid surprises. This is where the location-specific drivers can help ensure the hyperlocal risk information is reliable in crisis times.

Coarse global to fine hyperlocal

Global models provide seasonal outlooks and predictions at the short (1-3 days), medium (3-10 days), and extended (2-4 weeks) ranges. They have been getting better at offering outlooks of the monsoon, the El Niño and La Niña events, and early extreme-event warnings. Researchers around the world — in academia and national laboratories — constantly diagnose imperfections in these models and remove them.

One particular approach to improving the models is called downscaling, especially to enhance predictions of extreme events like small-scale heavy rain. In downscaling, researchers use a global model to drive local predictions in a higher resolution regional model to capture the weather at scales that the global model will miss.

Of late, they have been executing such two-tier strategies using techniques in artificial intelligence and machine learning (AI/ML). Their costs are lower than those incurred by running a high-resolution regional model. Such AI/ML approaches are also many times faster than regional models, further lending themselves to more effective disaster management.

Spotting location-specific amplifiers

Tragedies like that in Wayanad on July 30 tend to repeat themselves partly because their lessons are not always brought to bear on our understanding of the local amplifiers of extreme events. Simple changes in land use patterns — associated with urbanisation, say, or the deforestation of mountain slopes — could lead to a crushing cloudburst and or a punishing hailstorm.

The relatively more coarse resolutions of global models — which deal with changes in the tens of kilometres — tend to miss such local features and add to their imperfections. To acquire a better sense of the effects of these features and thus enable regional dynamic or AI/ML downscaling for hyperlocal predictions, we need more local data of weather and climate variables.

Disaster mitigation efforts are crucial to weather-proof the country and make it more climate-resilient at longer timescales. To this end we urgently need a data network that supports the mapping of local extreme event amplifiers.

Raghu Murtugudde is a professor, IIT Bombay, and emeritus professor, University of Maryland.

New Delhi:

High resolution images taken by Indian satellites show the widespread damage and devastation caused by landslides in Kerala’s Wayanad. More than 150 people have died and over 200 injured even as the rescue works are ongoing. The before and after images show that about 86,000 square meters of land slipped and the debris flowed for about 8 kilometers along the Iruvaiphuzha river. 

Interestingly the Indian Space Research Organisation report also presents evidence of an old landslide at the same location, suggesting its vulnerability was documented.

The National Remote Sensing Center, Hyderabad a part of the Indian Space Research Organization deployed its highest resolution Cartosat-3 optical satellite and the RISAT satellite that is capable of seeing through cloud cover. The space agency says the landslide was initiated at an altitude of 1550 meters above the sea level.

The latest report accessed by NDTV, suggests that there is evidence of an old landslide at the same location. A 2023 ‘Landslide Atlas of India’ prepared by ISRO had placed Wayanad region as a vulnerable to landslides.

ISRO satellite images show widespread devastation at Wayanad landslide. Almost 86,000 square meters of land slipped causing the landslide almost five times the size of the Rashtrapati Bhawan. The debris flowed for almost 8 kilometers downstream washing away towns and settlements. 

ISRO says there is evidence of an old landslide at same location. The National Remote Sensing Center used the Cartosat-3 satellite and the RISAT satellite to see through cloud cover.

The NRSC reports says “a major debris flow was triggered by heavy rainfall in and around the Chooralmala town of Wayanad District in Kerala state of India”.

Very high resolution RISAT SAR images of 31 July, 2024 show the entire extent of the debris flow from crown to end of run out zone. The approximate length of the flow is 8 km. The crown zone is a reactivation of an older landslide. The size of the main scarp of the landslide in 86,000 square meters. The debris flow has widened the course of the Iruvaniphuza River causing breach of its banks. Houses and other infrastructures located along the banks have been damaged by the debris flow, 3D rendition of the crown of the landslide illustrates that a large section of the hill slope has been affected. 

The areal extent of the landslide is 86,000 square meters. The crown is located at an approximate elevation of approximately 1,550 m above MSL.

ISRO prepared a “Landslide Atlas of India” which diligently documents the 80,000 landslides that have occurred over 20 years and lists landslide from Puthumala, Wayanad district, and large parts of Kerala are marked red as being prone to landslides.

Dr S Somanath, the Chairman of ISRO in the 2023 report says it presents “the overall landslide scenario in India and … the field of landslide hazard. I am sure that the atlas will be beneficial to everyone involved in disaster management endeavors.”

Thiruvananthapuram:

The Kerala police have launched an investigation into an alleged social media campaign against Chief Minister Pinarayi Vijayan’s Facebook post requesting help for the people affected by the landslides in Wayanad district.

The State Police Media Centre (SPMC) on Thursday said that the Wayanad Cybercrime police has registered a case under various provisions of the Bharatiya Nyaya Sanhita (BNS) and Disaster Management Act and launched a probe into the alleged spreading of a campaign with the intention of obstructing relief efforts.

The SPMC, in its statement, further said that the fake campaign was circulated on social media platform X from a handle called ‘Koyikodans 2.0’.

The post was aimed at motivating people to reject the Chief Minister’s appeal for disaster relief, it said.

The police warned of strict legal action under the law against those who edit, produce and disseminate fake posts in such a way so as to spread misconceptions.

For this, the cyber police have intensified monitoring of social media.

Vijayan had called upon everyone to contribute to the Chief Minister’s Disaster Relief Fund (CMDRF) in order to help those affected by the landslides.

Massive landslides triggered by torrential rains hit Mundakkai, Chooralmala, Attamala, and Noolpuzha hamlets in the early hours of Tuesday, killing several people, including women and children. 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

New Delhi:

At least 24 people have been killed and several are feared trapped after massive landslides hit Wayanad in the early hours today as heavy rainfall continued in Kerala.

250 members of the Fire and Rescue, Civil Defence, NDRF, and Local Emergency Response Teams are involved in the rescue operation. An additional team of NDRF has been directed to reach the spot immediately, the officials said.

Chief Minister Pinarayi Vijayan assured all possible rescue operations to be coordinated in the landslides in Wayanad.

Prime Minister Narendra Modi expressed anguish over the loss of lives in landslides and assured Chief Minister Pinarayi Vijayan of all possible help from the Centre to deal with the crisis.

The prime minister announced a compensation of Rs 2 lakh for the families of those who died. The injured would be given Rs 50,000.

Here are the Updates on Wayanad landslides:
 

• The Chief Minister has announced that the state Health Department has opened a control room. 
• Those in need of emergency assistance can contact authorities on helpline numbers 9656938689 and 8086010833.

• Besides the Kerala State Disaster Management Authority and NDRF, the Kannur Defence Security Corps are also set to join the rescue operation. 
• The Chief Minister also said two Air Force helicopters will depart for Wayanad shortly to join the ops.
• Chief Minister Pinarayi Vijayan has said all agencies have joined the rescue operation in Wayanad. 
• State ministers will coordinate the rescue ops, he has said in a statement.

• Prime Minister Narendra Modi has spoken to Kerala Chief Minister Pinarayi Vijayan and assured all help to the LDF government.
• The Prime Minister’s Office has announced compensation of Rs 2 lakh for the families of those killed in the calamity. Those injured would be given ₹ 50,000.

• At least eight people have died and hundreds are feared trapped after multiple landslides hit Kerala’s Wayanad district.
• Multiple agencies, including the National Disaster Response Forces, have joined the rescue ops in the hilly areas near Meppadi.