According to RMC, isolated heavy rainfall likely in Nilgiris, Chennai, Chengalpattu, Tiruvallur, and Villupuram on Wednesday.
| Photo Credit: R. RAGU

When a wall of water suddenly crashes from the sky and sweeps away homes and roads within minutes, one of the first words officials and the media in India reach for is ‘cloudburst’. However, the term is often misused in a way that can distract from poor planning and crumbling infrastructure.

What counts as a cloudburst?

According to the India Meteorological Department (IMD), a cloudburst occurs when a small area, around 20-30 sq. km, receives 10 cm or more of rain in an hour.

To put this in perspective, Indore receives 1,062 mm of rain every year on average. A cloudburst could dump nearly 10% of this in 60 minutes.

Heavy rains are a common feature of the southwest monsoon, but a cloudburst is still an extraordinary amount of rainfall and much rarer.

Because the water falls so quickly over a relatively small area, the ground cannot absorb all of it, leading to rapid and voluminous flooding.

Some scientists have also advocated for a category called ‘mini-cloudburst’, for 5 cm of rain in an hour over the same area, as, depending on the local topography, this can be devastating as well.

How common are cloudbursts in India?

Although cloudbursts are relatively rare, global warming, in particular as the atmosphere warms and can hold more moisture, is making them more frequent.

In response to a question, former Union Earth Sciences Minister Harsh Vardhan told Parliament in 2019 that between 1970 and 2016, the IMD had recorded only around 30 such incidents. However, many experts believe this number is an underestimate.

Counting them is not straightforward because most cloudbursts occur in remote, high-altitude regions such as the Himalaya and the Western Ghats, where rain gauges and weather stations are sparse.

In fact, if a cloudburst occurs a few kilometres away from a monitoring station, it may not be officially recorded as a cloudburst even if it causes large-scale destruction downstream.

Uttarakhand, Himachal Pradesh, and Jammu and Kashmir have, of late, reported a surge in events that locals have described as cloudbursts, especially in July and August.

How does a cloudburst form?

Contrary to the name, a cloudburst is not the literal bursting of a cloud, like a water balloon that has been popped.

A cloudburst typically begins with convection, when warm, moist air rises rapidly into the atmosphere. In mountainous areas, this is called orographic lifting, where monsoon winds are forced upwards by steep slopes.

As the air rises, it cools and condenses into towering cumulonimbus clouds, which can be up to 15 km tall.

Water droplets begin to form inside these clouds and, as they get heavier, they would normally fall as rain.

However, if the currents of warm air moving upwards are very strong, they can keep the raindrops suspended in the air for longer.

Eventually, the weight of the water droplets becomes too great for gravity and the updrafts to hold, or the updrafts weaken, sending the water plummeting down like an ocean descending on the ground.

Can the label obscure accountability?

The science of cloudbursts is clear, whereas the political use of the word ‘cloudburst’ is murky.

By calling a heavy downpour a ‘cloudburst’, authorities can turn it into a singular and unforeseeable act of nature, obscuring the role of human negligence.

That is, if the cause of a tragedy is said to be a ‘cloudburst’, the blame can be written off, which is harder to do when the real cause is “heavy rain combined with poor drainage”.

Following the 2022 floods in the Godavari basin in Telangana, then Chief Minister K. Chandrasekhar Rao said they might be the result of a “foreign conspiracy” involving cloudbursts.

However, independent experts said he was trying to draw attention away from the failure of the multibillion-dollar Kaleshwaram irrigation project, whose pump houses themselves were submerged.

In 2025, during the Dharali floods in Uttarakhand, initial reports blamed a cloudburst. However, meteorological data later showed that the actual rate of rainfall was much lower than the threshold for a cloudburst.

The underlying causes were illegal construction on riverbeds, deforestation that had left soil vulnerable to erosion, and the absence of drainage infrastructure along new “all weather” roads.

Had the downpour indeed been a cloudburst, officials may have been able to avoid questions about why the State had allowed buildings to be constructed in high-risk zones and why early warning systems failed.

Last week, the IMD rejected reports that Assam and Nagaland had experienced cloudbursts over the preceding few days and that they were responsible for the Upper Assam floods.

Are cloudbursts hard to forecast?

Cloudbursts are very difficult to forecast. Meteorologists can usually say whether a region is at risk of heavy rain but cannot say precisely which patch of land will experience a cloudburst.

First, most weather models study the atmosphere in grids and estimate the average weather for each cell.

A cloudburst, on the other hand, occurs over an area smaller than the size of each grid cell. To detect one, scientists need very high-resolution models, which in turn require immense computing power that is not always readily available.

Because of the mechanism through which cloudbursts form, they also develop and occur quickly. Cyclones and monsoon systems, on the other hand, can be tracked for weeks or even months, giving scientists more data to work with.

Finally, mountains are challenging environments for weather monitoring, and cloudbursts have a greater propensity to occur there.

For instance, Doppler weather radars work by emitting and receiving radar beams, which mountains can block, creating blind spots over many areas where cloudbursts are also more common.

Because the terrain is so rugged, there are also fewer automatic weather stations. If there are no sensors on the ground to tell a computer what is happening at a given moment, it cannot reliably predict what could happen in the next hour.

That said, the IMD is currently working on ‘nowcasting’, a technology that issues short-term alerts every few hours.

Under the Indian government’s new ‘Mission Mausam’, India also plans to more than double its radar network, from the current 40 or so, and use artificial intelligence to better predict hyperlocal events.

That said, even with the best technology, a cloudburst is likely to remain more difficult to predict than a typical rainstorm.

The India Meteorological Department (IMD) has issued a heatwave warning in 13 Telangana districts for Friday, June 19
| Photo Credit: India Meteorological Department

According to the India Meteorological Department, Hyderabad and its surrounding areas for the next 24 hours will see a generally cloudy sky.
| Photo Credit: India Meteorological Department

New Delhi:
Cyclone Dana has made landfall on the Odisha coast leading to heavy rain and strong winds in several areas. The storm made landfall between Bhitarkanika in the Kendrapara district and Dhamra in Bhadrak, with a wind speed of around 110 kmph.

Here Are 10 Points On Cyclone Dana:

Bhubaneswar/Kolkata:

A deep depression over east-central Bay of Bengal intensified into cyclonic storm ‘Dana’ on Wednesday morning, the India Meteorological Department (IMD) said.

The storm is likely to move in a northwestward direction, intensify further into a severe cyclonic storm over northwest Bay of Bengal and cross the Odisha-West Bengal coasts between Puri and Sagar Island in the early hours of October 25 with wind speeds of up to 120 kmph, the IMD added.

The system lay 560 km southeast of Paradip and 630 km south-southeast of Sagar Island at 5.30 am, it said.

Advising fishermen not to venture into the sea from October 23 to 25, the Met warned that wind speed is likely to reach 60 kilometres per hour (kmph) along and off Odisha-West Bengal coasts from October 23 and gradually increase to 100-110 kmph, gusting to 120 kmph, from October 24 night till October 25 morning.

More than 150 express/passenger trains running through South Eastern Railway jurisdiction have been cancelled in view of the severe cyclonic storm, an SER official said.

The trains cancelled were scheduled to depart their originating stations between October 23 and 25, the SER official said and added that more trains running through the SER zone may be cancelled if the situation demands.

The Kolkata-headquartered SER zone is spread over the states of West Bengal, Odisha and Jharkhand.

The Indian Coast Guard (ICG) said it is on high alert and has mobilised its vessels and aircraft to respond swiftly to any contingency over the Bay of Bengal.

It said the ICG has mobilised its vessels and aircraft, positioning them strategically to respond swiftly to any emergency situations. The NDRF said it has deployed 13 teams so far across south Bengal to respond to any emergency situation.

The storm is likely to bring very heavy rainfall in south Bengal districts on October 24 and 25, the IMD said.

Heavy to very heavy rainfall with extremely heavy downpour at one or two places is likely in the coastal districts of South 24 Parganas, Paschim Medinipur, Purba Medinipur and Jhargram districts.

Heavy to very heavy rainfall is likely in Kolkata, Howrah, Hooghly, North 24 Parganas, Purulia and Bankura districts between October 24 and 25, the Met said. 

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

New Delhi:

A total of 1,492 people died in India during extreme weather events in the 2024 monsoon season, according to data compiled by the India Meteorological Department.

The data revealed that 895 people lost their lives due to floods and rain-related incidents, while 597 fatalities were caused by thunderstorms and lightning strikes during the monsoon season.

The IMD reported that the country experienced 525 heavy rainfall events (precipitation between 115.6 mm and 204.5 mm) — the highest in the last five years — and 96 extremely heavy rainfall events (above 204.5 mm) during the 2024 monsoon.

According to the data, 17 people died from heatwaves — 13 in Jharkhand and four in Rajasthan — during the early part of the season.

Kerala, which witnessed devastating landslides in the ecologically fragile Wayanad district on July 30, recorded 397 deaths due to floods and heavy rains.

Assam and Madhya Pradesh recorded 102 and 100 deaths, respectively, due to floods and heavy rains.

In the national capital, 13 deaths were reported as a result of floods and heavy rains.

The data also revealed that Madhya Pradesh recorded the highest number of deaths (189) due to thunderstorms and lightning strikes, followed by Uttar Pradesh (138), Bihar (61), and Jharkhand (53).

The 2024 southwest monsoon season officially ended on Monday, with India recording 934.8 mm of rainfall — 107.6 per cent of the long-period average and the highest since 2020.

Central India received 19 per cent more rainfall than the long-period average for the region, the southern peninsula recorded 14 per cent more than normal, and northwest India saw 7 per cent more than usual.

In contrast, east and northeast India registered 14 per cent less rainfall than normal, according to the data.

The country experienced an 11 per cent rainfall deficit in June, followed by an excess of 9 per cent in July, 15.3 per cent in August, and 11.6 per cent in September.

Only three meteorological subdivisions recorded deficient rainfall this monsoon season.

India’s geographical area is divided into 36 meteorological subdivisions. Twenty-one subdivisions recorded normal rainfall, 10 experienced excess rainfall, and two saw large excess rainfall. 

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

New Delhi:

After a wetter-than-normal August, India is likely to experience above normal rainfall in September, with heavy to very heavy precipitation expected in northwest India and the surrounding areas.

Above normal rainfall is likely over most parts of India, except for some areas in extreme northwest India, many parts of the southern peninsula, northern Bihar, and northeastern Uttar Pradesh, as well as most of northeast India, where below normal rainfall is expected, the IMD said.

Addressing a virtual press conference, IMD Director General Mrutyunjay Mohapatra said that the country is expected to receive above normal rainfall in September, at 109 per cent of the long-period average of 167.9 mm.

Heavy to very heavy rainfall is anticipated in the northwest region, including Uttarakhand, parts of Himachal Pradesh, Jammu and Kashmir, Rajasthan, and the adjoining areas of Madhya Pradesh.

“There could be episodes of extremely heavy rainfall in these areas, potentially leading to floods. We should remain cautious of landslides, mudslides, and landslips,” Mohapatra said.

“We anticipate a low-pressure system developing over the Bay of Bengal each week of the month, which will result in significant rainfall across the country,” he added.

The monsoon trough is expected to remain in its normal position, with the possibility of several low-pressure systems developing in the Bay of Bengal, which may travel towards west-northwest up to Rajasthan. The trough could also shift towards the foothills of the Himalayas, and there is a potential for a western disturbance to affect the region in September, Mohapatra said. 

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

Mumbai Weather Live Updates: Heavy rains have battered Mumbai with the city recording over 300 mm of rainfall at several places in just six hours from 1 am to 7 am today. Several trains were diverted and many others were cancelled following heavy rains, the Central Railways said. The Brihanmumbai Municipal Corporation is working to clear waterlogging across the city.  

The India Meteorological Department (IMD) has issued an orange alert for Mumbai, Thane, Palghar and the Konkan belt. Vikhroli’s Veer Savarkar Marg Municipal School and MCMCR Powai saw the highest rainfall in the last 24 hours and over 315 mm of rainfall was recorded. Water-logging was reported from Worli, Buntara Bhavan, in Kurla East, King’s Circle area of Mumbai, Dadar and Vidyavihar Railway Station.

Here are the LIVE updates on Mumbai rain: 

Mumbai Rain LIVE: Check List Of BEST Buses Diverted Due To Waterlogging

#Mumbai | Due to waterlogging triggered by rain, many BEST buses diverted from their regular route, says BEST Bus Transport.

(Reported by news agency ANI) #MumbaiRainspic.twitter.com/XsEk7cHNbM

– NDTV (@ndtv) July 8, 2024

Mumbai Rain LIVE: These Trains Have Been Cancelled

Due to Water logging in BB div in Various Station Following Trains are Re-Schedule, Short terminated and Short originated as follow pic.twitter.com/iaP79Nx9gi

– DRM Mumbai CR (@drmmumbaicr) July 8, 2024

List Of Areas That Recorded Heaviest Rainfall In Mumbai

Locations with heaviest rainfall in Mumbai city and suburbs on July 8

– Veer Savarkar Marg Municipal School (315.6 mm)

– MCMCR Powai (314.6 mm)

– Malpa Dongri Municipal School (292.2 mm)

– Chakala Municipal School (278.2 mm)

– Aarey Vasahat Municipal Corporation School (259.0 mm)

– Hindu Hrudayamrat Balasaheb Thackeray Municipal School (255.0 mm)

– Naryalwadi School (241.6 mm)

– Collector Colony Municipal School (221.2 mm)

– Pratikshanagar Municipal Corporation School (220.2 mm)

– Nutan Vidyamandir (190.6 mm)

– Lal Bahadur Shastri Marg Municipal School (189.0 mm)

– Shivdi Koliwada Municipal School (185.8 mm)

– Rawali Camp (176.3 mm)

– Dharavi Black Fort Municipal School (165.8 mm)

– B. Nadkarni Udyan Municipal School (156.6 mm)

Water Pumps Used To Drain Water From Rail Tracks In Mumbai Amid Rain

#MumbaiRains | Despite the heavy rain, #MumbaiLocals in Western Railway’s suburban section are running normally.

“High capacity water pumps are being utilised to drain water and railway staff across the section are closely monitoring the situation to keep Mumbai’s lifeline… pic.twitter.com/1nPRH7OZWO

– NDTV (@ndtv) July 8, 2024