Five dead in Jammu and Kashmir's Kishtwar following cloudburst: Why are they dangerous and which areas are prone to it

On Wednesday, grim news of flash floods triggered by a cloudburst in a remote village in Kishtwar district of Jammu and Kashmir of where five bodies were recovered on so far Wednesday after some houses were swept away.

In another incident, at least one person was killed while 10 went missing as flash floods triggered by incessant rains lashed Himachal Pradesh on Wednesday. Moreover, one mini-hydropower project at Sangra in the Sanku division was damaged and some houses were damaged at Khangral on Kargil-Leh National Highway in Ladakh by cloudbursts.

What is a cloudburst?

A cloudburst is a sudden aggressive rainstorm falling for a short period of time, limited to a small geographical area. Meteorologists say the rain 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.

Generally, cloudbursts are associated with thunderstorms and the air currents rushing upwards in a rainstorm hold up a large amount of water. If these currents suddenly cease, the entire amount of water descends onto a small area with catastrophic force all of a sudden and causes mass destruction. This is due to a rapid condensation of the clouds.

Why is a cloudburst dangerous?

Because of the amount of rain involved, a cloudburst can be quite dangerous, especially if it lasts for several hours. Flooding is common with cloudbursts, sweeping away people, animals and land on its way. Topographical conditions like steep hills favour the formation of these clouds. Water flowing down steep slopes brings debris, boulders and uprooted trees with great velocity damaging any structure that comes in their way.

Often, these severe rainstorms appear in the summer, and in farming communities, they are sometimes welcomed, as a cloudburst can irrigate crops very thoroughly.

Where does cloudburst happen?

It usually occurs in high-altitude areas due to the formation of a low-pressure area on the top of a mountain. The low-pressure zone attracts clouds to the top of the mountain with great force. When they hit the peak, the moisture content is released in the form of rain. In some cloudbursts, up to 5 inches (almost 13 centimeters) of rain can fall in an hour, often in the form of extremely large droplets. All heavy rains are not necessarily cloudbursts.

They are called 'bursts' probably because it was believed earlier that clouds were solid masses full of water. So, these violent storms were attributed to their bursting.

Cloudbursts frequently occur in Himachal Pradesh, Uttarakhand and Jammu and Kashmir during the monsoon. Cloudburst is a natural and common phenomenon in the Himalayas, especially in the Garhwal and Kumaon regions of Uttarakhand. Cloudburst and associated disasters affect thousands of people every year and cause loss of life, property, livelihood, infrastructure and environment.

Why cloudbursts are hard to predict

There is no satisfactory technique for anticipating the occurrence of cloud bursts because of their small scale. A very fine network of radars is required to be able to detect the likelihood of a cloud burst and this would be prohibitively expensive. Only the areas likely to receive heavy rainfall can be identified on a short-range scale. Much of the damage can be avoided by way of identifying the areas and the meteorological situations that favour the occurrence of cloud bursts.

Big cloudbursts in India

• August 2019: The cloud burst took place around 4 am in Pathar Katta village. Heavy rainfall led to flash floods in Chad a local nullah causing severe damages to properties.
• May 2, 2018: It happened at Chida area of Narayan Bagar block in Chamoli district. In the Jeet Singh market area, several vehicles were seen trapped in the debris and mud flushed down through Talla Gadera (seasonal stream) on Karnprayag-Gwaldam Highway blocking the road for about half an hour.
• June 2013: Cloudburst occurred at Kedarnath in Rudraprayag in Uttarakhand.
• 9 June, 2011: near Jammu, cloudbursts left four persons dead and over several injured in Doda-Batote highway, 135kms from Jammu. Two restaurants and many shops were washed away
• September 2012: Cloud burst happened at Ukhimath in Uttarakhand.
• September 2010: Cloud burst in Almora in Uttrakhand has drowned away two villages one of them being Balta, leaving a few people alive and the rest entire village dead and drowned. Almora has been declared as a town suffering from the brunt of cloudburst by authorities of Uttrakhand. Had there been a bit more swaying of clouds, the town of Ranikhet must have drowned also.
• 6 August, 2010: in Leh, a series of cloudbursts left 179 persons dead and over 400 injured in the frontier Leh town of Ladakh region in Jammu and Kashmir.
• 7 August, 2009: 38 people were killed in a landslide resulting from a cloudburst in Nachni area near Munsiyari in Pithoragarh district of Uttarakhand.
• 16 August, 2007: 52 people were confirmed dead when a severe cloud burst occurred in Bhavi village in Ghanvi, Himachal Pradesh.
• 26 July, 2005: A cloudburst caused approximately 950 millimetres (37 in) of rainfall in Mumbai. over a span of eight to ten hours; the deluge completely paralysed India's largest city and financial centre.
• 6 July, 2004: At least 17 people were killed and 28 injured when three vehicles were swept into the Alaknanda river by heavy landslides triggered by a cloudburst that left nearly 5,000 pilgrims stranded near the Badrinath shrine area in Chamoli district, Uttarakhand.
• 16 July, 2003: About 40 persons were killed in flash floods caused by a cloudburst at Shilagarh in the Gursa area of Kullu, Himachal Pradesh.
• 17 August, 1998: A massive landslide following heavy rain and a cloudburst at Malpa village killed 250 people including 60 Kailash Mansarovar pilgrims in Kali valley of the Kumaon division, Uttarakhand. Among the dead was Odissi dancer Protima Bedi.
• 15 August, 1997: 115 people were killed when a cloud burst came bustling and trail of death are all that is left behind in Chirgaon in Shimla district, Himachal Pradesh.
• July 1970: Cloudburst in the upper catchment area led to a 15-metre rise in the Alaknanda river in Uttarakhand. The entire river basin, from Hanumanchatti near the pilgrimage town of Badrinath to Haridwar, was affected. An entire village was swept away.
• 28 September, 1908: A cloudburst resulted in a flood where the Musi River was swollen up to 38-45 m. About 15,000 people were killed and around 80,000 houses were destroyed along the banks of this river.