Cloudbursts

News: Recently, cloudbursts have been reported from several places in J&K, Ladakh, Uttarakhand and Himachal Pradesh.

About:

  • Cloudbursts are short-duration, intense rainfall events over a small area.
  • It is a weather phenomenon with unexpected precipitation exceeding 100mm/h over a geographical region of approximately 20-30 square km.
  • In the Indian Subcontinent, it generally occurs when a monsoon cloud drifts northwards, from the Bay of Bengal or the Arabian Sea across the plains then on to the Himalaya that sometimes brings 75 millimeters of rain per hour.
  • The relative humidity and cloud cover is at the maximum level with low temperature and slow winds because of which a high number of clouds may get condensed at a very rapid rate and result in a cloudburst.
  • As temperatures increase, the atmosphere can hold more and more moisture and this moisture comes down as a short very intense rainfall for a short duration probably half an hour or one hour resulting in flash floods in the mountainous areas and urban floods in the cities.
  • Difference between Rainfall and Cloudbursts:
    • Rain is condensed water falling from a cloud while cloudburst is a sudden heavy rainstorm.
    • Rain over 100mm per hour is categorised as a cloudburst.
    • The cloudburst is a natural phenomenon, but occurs quite unexpectedly, very abruptly, and rather drenching.

Impact of climate change on Cloudbursts:

  • Several studies have shown that climate change will increase the frequency and intensity of cloudbursts in many cities across the globe. As temperatures increase the atmosphere can hold more and more moisture and this moisture comes down as a short very intense rainfall for a short duration.
  • This results in flash floods in the mountainous areas and urban floods in the cities. Also, there is evidence suggesting that globally short duration rainfall extremes are going to become more intense and frequent.