0.1569
900 319 0030
x

Cloud Burst in Himachal Pradesh

iasparliament Logo
August 25, 2023

Why in news?

Himachal Pradesh witnessed a heavy rainfall along with landslides in which at least 22 people died.

What is a cloud burst?

According to the Indian Meteorological Department, an event of extremely heavy rainfall is determined as a cloudburst when "10 cm rainfall is received at a station in one hour”

  • It is an extremely high amount of precipitation in a short span of time.
  • It is a localised but intense rainfall activity that can cause widespread destruction, especially in hilly regions.
  • Region- It usually occurs over a small geographical region (20-30 sq.km).
  • Criteria- Rainfall of 10 cm or more in an hour over a roughly 10 km x 10-km area is classified as a cloudburst event.
  • By this definition, 5 cm of rainfall in a half-hour period over the same area would also be categorized as a cloudburst.
  • Mechanism- It happens when saturated clouds are unable to produce rain because of the upward movement of very warm current of air.
  • Cloud formation- This updraft movement of warm wind along with clouds forms the Cumulonimbus clouds.
  • It can grow up to 12-15 km in height through the entire troposphere (occasionally up to 21 km) and can hold huge amounts of water
  • Instead of dropping down, raindrops get bigger in size and get pushed up due to the air current.
  •  Eventually they become too heavy to hold and drop down, leading to more rain than usual.

cloudbursts

What are the causes of cloud burst?

  • Monsoon- It often occurs during monsoon season when the South West Monsoon winds bring in large amount of moisture which fuels the cloudburst.
  • Orographic lift- It is affected by factors like local topology, wind systems, and temperature gradients between the lower and upper atmosphere.
  • Thunderstorm- It is caused due to excessive amount of condensation in the cloud during thunderstorm.
  • Climate change- Global warming is leading to more evaporation of water and because of this dense cumulonimbus clouds are forming, resulting in intense rainfall.
    • Even 1 degree Celsius rise in global temperature can cause change in monsoon extremes and frequent cloudburst.

What are the areas prone to cloudburst?

  • Regions more prone-
    • The Himalayas
    • Western Ghats
    • Northeastern hill States of India
    • Coastal regions
  • Landslides- 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.
  • Coastal cities- They are particularly vulnerable to cloudbursts since the flash floods make the conventional stormwater and flood management policies in these cities dysfunctional.
    • Example- Chennai Floods 2015.

Recent cloudbursts

  • Himachal Pradesh-2003
  • Ladakh-2010
  • Uttarakhand-2013
  • Northeastern states and Western Ghats- 2022 monsoon

What are the consequences of cloud burst?

  • Landslide- The movement of rocks or debris on a slope downwards is called as Landslide.
  • Human loss and property loss - There is a rise in death toll and loss of property due to cloudburst.
  • Spread of communicable diseases - Waterborne diseases (cholera, typhoid fever etc.,), vector-borne diseases (dengue, malaria etc.,) spreads rapidly during floods.
  • Impact on agriculture - It destroys large number of crops and impacts the food security of the country. Livestock also gets displaced during floods.
  • Disruption of communication - It damages transportation links such as bridges, rail, and power plants thus causing communication disruption.
  • Economic and social disruption - The economy comes to a standstill as people are forced to move to another place.

What are the challenges associated in detecting cloudbursts?

  • Forecast - Specific cloudburst events cannot be forecast.
  • Possibility of extremely heavy rainfall, which could result in cloudburst kind of situations, are forecast six to 12 hours in advance.
  • Failure of satellite- They fail to detect cloudburst systems as the precipitation radars are much smaller than the areas of individual cloudburst events.
  • High cost- Radars need to installed in wide areas for a wider coverage. Installing radars is expensive.
  • Technological hurdle- It is difficult for any metrological agency to predict exactly how much rain is likely to fall at any given place.
  • Although it is difficult to forecast cloudbursts, doppler radars can be helpful in predicting them.
  • Lack of feasibility - It requires a very dense network of weather instruments, and computing capabilities that seems unfeasible with current technologies

What lies ahead?

  • Multiple Doppler weather radars can monitor moving cloud droplets and help to provide forecast for the next 3 hours.
  • Proper community sensitisation regarding the causes, effects and safety precautions of cloudbursts is the need of the hour.

 

References

  1. Indian Express- Himachal Pradesh cloudburst explained
  2. The Times of India- State declared as natural calamity affected area
Login or Register to Post Comments
There are no reviews yet. Be the first one to review.

ARCHIVES

MONTH/YEARWISE ARCHIVES

Free UPSC Interview Guidance Programme