How does a cloud burst?

Pukhtun Nama Web Story

The Clifton area of ​​Karachi recorded 130 mm (just over five inches) of rain in an hour on August 27, which meteorologists described as the result of a ‘cloudburst’. Similarly, on August 29, a sudden downpour of rain in different parts of Khyber Pakhtunkhwa caused a cloudburst, killing 20 people and injuring several others.

During the recent monsoon, cloudbursts have also occurred in the Neelum, Sharda and Kail valleys of Azad Kashmir, resulting in reports of heavy loss of life and property due to landslides and floods.

A cloud burst is a weather situation in which a lot of rain falls in a very short time. Large hailstorms with heavy thunderstorms can occur during this time and the amount of rain can reach 25 mm (about an inch) in a few minutes.

This situation occurs when the warm air, which is found just above the surface of the earth, hits the lower part of the clouds and prevents them from raining. As a result of this collision, the process of converting vapor into water in clouds becomes much faster.In this condition, where new raindrops are formed in the clouds, the hot air also pushes the old raindrops back into the clouds. As the air passing under these clouds cools down, the clouds suddenly ‘burst’.This situation occurs during the monsoon season when the clouds rising from the Bay of Bengal and the Arabian Sea cross the plains and head towards the Himalayan mountains. Therefore, cloudbursts in Pakistan usually occur in the northern mountainous areas, of which the Neelum Valley in Kashmir is particularly noteworthy.Last year, 22 people were killed and more than 50 injured in flash floods caused by cloudbursts in the valley’s village of Lesva. The Meteorological Department has forecast a number of cloudbursts in the north this year as well.

The following are some of the key cloudburst events in Pakistan:

July 1, 1977: Karachi
Rainfall of 207 mm (eight inches) was recorded in 24 hours

July 23, 2001: Islamabad
620 mm (twenty four inches) of rain was recorded in ten hours. Nowhere in Pakistan has there been so much rain in the last hundred years

July 23, 2001: Rawalpindi
335 mm (thirteen inches) of rain was recorded in ten hours

July 18, 2009: Karachi
245 mm (nine and a half inches) of rain was recorded in four hours

July 29, 2010: Peshawar
274 mm (just under 11 inches) of rain was recorded in 24 hours

August 9, 2011: Islamabad
176 mm (seven inches) of rain was recorded in three hours

How it different from normal rainfall?
Rain is condensed water falling from a cloud while cloudburst is a sudden heavy rainstorm. A report in the Down to Earth said a cloudburst is different from rain only in the amount of rainfall recorded. Rain over 100mm per hour is categorised as a cloudburst.