What is a cloudburst?

A cloudburst is sudden copious rainfall. It 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. 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 on to a small area with catastrophic force all of a sudden and causes mass destruction. This is due to a rapid condensation of the clouds.

They occur most often in desert and mountainous regions, and in interior regions of continental landmasses.

During a cloudburst, more than 2 cm of rain may fall in a few minutes. 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.

One of the major disasters from a cloudburst in India occurred in 2002 in Uttaranchal. Some 28 people died when villages like Marwari, Kotsisham, Matgoan and Agonda were hit by sudden cloudbursts.

Cloudbursts frequently occur in Himachal Pradesh during the monsoon.

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