Cloudbursts

In News: Highly-localised rains in Amarnath, J&K, caused flooding and loss of lives.

What is a cloudburst?

• A cloudburst refers to an extreme amount of rain that happens in a short period, sometimes accompanied by hail and thunder.
• The India Meteorological Department (IMD) defines it as unexpected precipitation exceeding 100mm (or 10 cm) per hour over a geographical region of approximately 20 to 30 square km.
• Basically, all instances of cloudbursts involve heavy rain in a short period, but all instances of heavy rain in a short period are not cloudbursts if they do not fit this criterion.

Why do cloudbursts occur in hilly areas?

• Due to their definition dealing with a very small area, it is difficult to accurately predict and identify cloudbursts immediately.
• However, they are more likely to occur in mountainous zones mainly because of terrain and elevation.
• This is because, in hilly areas, sometimes saturated clouds ready to condense into rain cannot produce rain, due to the upward movement of the very warm current of air.
• Instead of falling downwards, raindrops are carried upwards by the air current. New drops are formed and existing raindrops increase in size.
• After a point, the raindrops become too heavy for the cloud to hold on to, and they drop down together in a quick flash.

Source: Indian Express

Previous Year Question

Q.1) Consider the following statements: (2020)

1. Jet streams occur in the Northern Hemisphere only.
2. Only some cyclones develop an eye.
3. The temperature inside the eye of a cyclone is nearly 10°C lesser than that of the surroundings.

Which of the statements given above is/are correct?

1. 1 only
2. 2 and 3 only
3. 2 only
4. 1 and 3 only