Prof. B L Kaul
The cloudburst at Honzar a remote village in Dachhan area of Kishtwar district on midnight of 27 July 2021 in which 7 people were killed and 19 went missing was followed by one near the holy cave of Amarnath and another at Aloosa in Bandipore district made me sit up and think. Called “Trath” in Kashmiri and ” Badal phatna” in Hindi/ Urdu I witnessed it happen at Pahalgam in 1968 and it was reported widely in press . It had destroyed many landmarks like the old hospital complex , some private buildings , hotels, the famous Pahalgam Club (then situated on the “Island” between the two branches of the Lidder river) and the bridge connecting it with the town. Such was the ferocity of the cloudburst that besides the loss of property several tourists , hotel owners and their staff lost their lives.
What is a Cloudburst?
Cloudburst is a sudden heavy rainfall, usually local in nature and of brief duration. Most Cloudbursts occur in connection with thunderstorms. In these storms there are violent uprushes of warm air, which prevent the condensing of raindrops from falling to the ground. A large quantity of water may thus accumulate at high levels, and if upward currents of air are weakened the whole of this water falls at a time and takes with it everything that comes in its way.
Cloudbursts are especially common in mountainous areas. This is probably because the warm air currents of a thunderstorm tend to follow the upward slope of a mountain. The effects of the heavy rainfall are especially striking on mountain slopes because the falling water is concentrated in valleys and gulleys. Cloudbursts in mountains cause sudden destructive floods.
A Cloudburst can simply be defined as, ” a sudden copious and aggressive rainstorm falling for a short period of time limited to a small geographical area”. Meteorologists say the rainfall from a Cloudburst is usually of the shower type with a fall rate equal to or greater than 100 mm (4.94 inches) per hour.
History of Cloudbursts
Cloudbursts are as old as the mother earth. Their recording is as old as the science of modern meteorology. According to recent records a rainfall of 63 mm (2.47 inches) in 3 minutes was registered by an automatic rain gauge ar Porto Bello, Panama, on Nov.29, 1911. Similarly 38 mm (1.50 inches) rainfall in 1 minute was registered by Barotrain gauge near Abmyes, Guadeloupe (a French overseas Island region in Carribbean) on Nov.26,1970.
In the Indian subcontinent, a cloudburst usually occurs when a monsoon cloud drifts northwards from the Bay of Bengal or Arabian sea across the plains, then onto the Himalayas and bursts, bringing rainfall as high as 75mm/ hour. During monsoon season especially in hill states like Uttarakhand, Himachal Pradesh and Union territories of Jammu and Kashmir and Ladakh. Cloudbursts can wreck a lot of damage to roads, properties and forests besides killing humans, livestock and wildlife. The Kedarnath tragedy in 2013 which claimed more than 5700 human lives, most of them pilgrims, is still alive in our memory. The recent Rishi Ganga- Dhauli Ganga flood fury flood fury also caused massive damages besides killing hundreds of humans and livestock.
A recent study made by experts A.P.Dimri et al titled “Cloudbursts in Indian Himalayas : A Review” published in online Journal of Hydrometetrology on 01 July 2020 has mentioned 30 Cloudbursts from 20 July 1970 to 28 May 2016. These are mostly from Uttarakhand and Himachal Pradesh but also include those in Ladakh, Jammu and Kashmir. According to the study at least eight cloudbursts occurred in Kashmir valley at Budgam, Kupwara, Ganderbal, Sonamarg, Pahalgam and Baltal in a period of 3 weeks in the month of July 2015 killing at least 20 people and destroying property worth crores of rupees. The Ladakh region met with a deluge on 06 August 2010. Overnight floods affected as many as 71 villages ,towns and Leh city. It killed 255 people including 6 foreign tourists and 1749 houses were destroyed
Prediction of cloudbursts
The question that most people ask is whether Cloudbursts can be predicted.According to Director General of Indian Meteorogical Department (IMD) Mretinjay Mahapatra,” Cloudbursts can not be predicted, but we do give alerts of heavy rains. In case of Himachal Pradesh, we had given a red (colour- coded alert)”. To monitor or Nowcast (forecasting few hours lead time) the cloudburst we need to have dense radar network over the cloudburst- prone areas or we need to have high resolution weather forecasting models to resolve the scale of the cloudburst ( IMD).
According to a written response by Earth Science Minister Dr. Jitender Singh in the LokSabha on July 23, 2021 the Himalayan region has seven Doppler weather radars- 2 in Jammu and Kashmir (Sonamarg and Srinagar), one each in Kufri and Mukteshwar ( Uttarakhand), Mohanbari (Assam), Sohri ( Meghalaya), and Agartala ( Tripura). He further said that two more Doppler weather radars will be installed in Himachal Pradesh by December 2022.
In my opinion looking at the frequency of Cloudbursts in the Himalayas we will need a dense network of very high resolution weather forecasting equipment over the cloudburst prone areas.
Can Cloudbursts be prevented?
M. Rajeevan, Secretary, Ministry of Earth Sciences recently said the incidents of Cloudbursts seem to be increasing. He said that although, it is difficult to forecast cloudbursts, yet Doppler radars can be very helpful in predicting them. However, the big question that needs to be answered is whether Cloudbursts can be prevented. To my mind the frequent occurrence of Cloudbursts in recent times is directly related to global warming and human interference. That global warming is caused by carbon emissions is a well known fact. It is also known that climate change is a direct result of global warming. So if the carbon emissions are reduced by reducing use of fossil fuels and vigorously going for alternate sources of energy like solar and wind energy, these steps will certainly help in reducing Cloudbursts, even if they can’t be altogether prevented. Hydrogen can also play a big role in the power sector and help reduce carbon emissions directly and reduce occurrence of Cloudbursts indirectly.
Although Cloudbursts can not be stopped altogether yet the following measures can mitigate the impact of Cloudbursts in the Himalayas:
Regulation of construction activities along river banks with special consideration to water level during heavy rainfall. Adoption of eco-friendly policies and ecosensitive tourism in the mountainous areas.
(The author is an environmentalist)
Prof. B L Kaul