Cloudburst

Cloudburst Latest News

Recently, the Ramban district of Jammu and Kashmir witnessed torrential rainfall and hail, resulting in severe damage.

• The India Meteorological Department (IMD) reported 16.9 mm of rainfall in 24 hours, marking a 575% increase from the normal 2.5 mm.

What is a Cloudburst?

• A cloudburst is a localised and extremely intense rainfall event, defined by rainfall of 10 cm or more within one hour over an area of approximately 10 km × 10 km.
• Even 5 cm of rain in 30 minutes over the same area qualifies as a cloudburst.
• Cloudbursts are more common in mountainous regions due to a process known as orographic lift. In this phenomenon:
  • Warm air ascends the mountain slope and expands due to lower atmospheric pressure at higher altitudes.
  • As it expands and cools, the air releases its moisture in the form of precipitation.
  • When large volumes of warm, moist air keep rising and accumulating moisture without releasing it, it can lead to a sudden, violent downpour.
• Because of their localised nature, cloudbursts are difficult to forecast and can overwhelm drainage systems, resulting in flash floods and landslides.

What is a Flash Flood?

• A flash flood is a sudden and rapid inundation that occurs when excessive rainwater enters streams, drains, or rivers, often overwhelming the natural or built drainage capacity.
• These are more frequent in mountainous regions where the rocky terrain absorbs little water, causing more surface runoff.
• Unlike riverine floods in plains that cause long-term property damage, flash floods tend to be more deadly, often catching people off guard and leading to loss of life.

What is a Landslide?

• A landslide refers to the movement of rock, debris, or earth down a slope, typically triggered when the force of gravity exceeds the resisting strength of the slope.
• Heavy rainfall plays a critical role in causing landslides by:
  • Increasing the weight of the slope material.
  • Reducing cohesion and friction, which makes it easier for soil and rocks to slide.
• Water infiltration from intense rain destabilises the slope, making landslides more likely.
• Landslides can:
  • Crush living beings under debris.
  • Disrupt roads and transportation.
  • Block rivers, potentially causing secondary flooding.

Cloudburst FAQs

Q1. What is a Cloudburst?
Ans. A cloudburst is an extremely intense rainfall event, usually localised, where more than 100 mm of rain may fall in an hour, often leading to flash floods.

Q2. Where are cloudbursts most common in India?
Ans. They frequently occur in the Himalayan regions, especially in Uttarakhand, Himachal Pradesh, and Jammu & Kashmir, due to orographic lift and weather instability.

Q3. What causes a cloudburst?
Ans. It results from the sudden condensation of moisture-laden clouds, often enhanced by topography and local convergence zones.

Source: IE