Cloudbursts

• 30 Jul 2021

Why in News

Recently, cloudbursts have been reported from several places in India.

Key Points

• 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 millimetres of rain per hour.
• Occurrence:
  
  • The relative humidity and cloud cover is at the maximum level with low temperature and slow winds because of which a high amount 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.
• Cloudburst are Different from Rainfall:
  
  • 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:
  
  • Several studies have shown that climate change will increase the frequency and intensity of cloudbursts in many cities across the globe.
    
    • In May 2021, the World Meteorological Organization noted that there is about a 40% chance of the annual average global temperature temporarily reaching 1.5°C above the pre-industrial level in at least one of the next five years.
    • It added that there is a 90% likelihood of at least one year between 2021 and 2025 becoming the warmest on record and dislodge 2016 from the top rank.
  • It is seen that more cloudbursts are happening in Himalayan region because the decadal temperature rise in the Himalayan region is higher than the global rate of rising temperatures.
• Consequences of Cloudbursts:
  
  • Flash floods.
  • Landslides
  • Mudflows
  • Land caving.
• Prediction:
  
  • There is no satisfactory technique for anticipating the occurrence of cloud bursts because they develop over a small period of time.
  • A very fine net work of radars is required to be able to detect the likelihood of a cloud burst and this would be expensive.
  • Only the areas likely to receive heavy rainfall can be identified on a short range scale. Much of the damage can be avoided by way of identifying the areas and the meteorological situations that favour the occurrence of cloud bursts.

Source: IE