QUESTION 

Explain the mechanism and occurrence of cloudburst in the context of the Indian subcontinent. Discuss two recent examples.

(250 words, 15 marks)

Introduction:

·   A cloudburst is a localised but intense rainfall over a small geographical area that can cause widespread destruction, especially in hilly regions where this phenomenon is most common.

·   According to the Indian Meteorological Department, if 10 cm of rainfall is received at a station in one hour, the rain event is termed a cloud burst. Predicting the cloud bursts is difficult due to their very small scale in space and time.

Body:

·     In India, cloudbursts often occur during the monsoon season, when the southwesterly monsoon winds bring copious amounts of moisture inland.

·    The moist air that converges over land gets lifted as it encounters the hills. The moist air reaches an altitude and gets saturated, and the water starts condensing out of the air, forming clouds.

·  This is how clouds usually form, but such an orographic lifting together with a strong moisture convergence can lead to intense cumulonimbus clouds taking in huge volumes of moisture that are dumped during cloudbursts.

·      Tall cumulonimbus clouds can develop in about half an hour as the moisture updraft happens rapidly, at a pace of 60 to 120 km/hr.

·      A single-cell cloud may last for an hour and dump all the rain in the last 20 to 30 minutes, while some of these clouds merge to form multi-cell storms and last for several hours.

·       Cloudbursts occur mostly over the rugged terrain of the Himalayas, Western Ghats, and northeastern hill states of India.

·   The heavy spells of rain on the fragile steep slopes trigger landslides, debris flows, and flash floods, causing large-scale destruction and loss of people and property.

Recent Cloudburst Events

— On July 8, 2022, flash floods occurred in the Lidder Valley en route to Amarnath Temple in Jammu and Kashmir, taking the lives of several pilgrims.

— Himachal Pradesh (2003), Ladakh (2010) and Uttarakhand (2013)

Conclusion:

Ground monitoring stations can hardly capture the characteristics of cloudbursts due to their highly localised and short occurrences. Hence, most of these events go unreported due to the lack of monitoring mechanisms in the region, weakening our ability to understand them from a complete perspective.