What is a Shelf Cloud?

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What is a Shelf Cloud? Blog Image


A terrifying shelf cloud recently appeared in Uttarakhand’s Haridwar.

About Shelf Cloud:


  • A “shelf cloud” or “Arcus cloud” generally forms along the leading edge of thunderstorms.
  • It is a type of low-lying, horizontal cloud formation characterized by a clearly defined line of solid clouds.
  • It is known for its distinctive wedge-shaped formation. They usually appear as a broad arc across the sky that can sometimes appear to be rotating horizontally.
  • Formation
    • Shelf clouds form when cold and dense air is forced into a warmer air mass by wind.
    • This rush of cold air often occurs in a thunderstorm’s downdraught, where cold air rushes towards the ground before spreading out to create a gust front.
    • Shelf clouds produced by thunderstorms are always preceded by a rush of dry and cold air ahead of the cloud, with rain arriving after the shelf cloud has passed overhead.


What is a Thunderstorm?

  • A thunderstorm is a rain shower during which you hear thunder. Since thunder comes from lightning, all thunderstorms have lightning.
  • Formation:
    • Thunderstorms form when warm, moist air rises into cold air. 
    • The warm air becomes cooler, which causes moisture, called water vapor, to form small water droplets — a process called condensation.
    • The cooled air drops lower in the atmosphere, warms, and rises again.
    • This circuit of rising and falling air is called a convection cell. 
    • If this happens a small amount, a cloud will form. If this happens with large amounts of air and moisture, a thunderstorm can form.


Q1) What is an Air Mass?

Air mass, in meteorology, is a large body of air having nearly uniform conditions of temperature and humidity at any given level of altitude. Such a mass has distinct boundaries and may extend hundreds or thousands of kilometers horizontally and sometimes as high as the top of the troposphere (about 10–18 km [6–11 miles] above the Earth’s surface).

Source: Terrifying 'Shelf Cloud' Reportedly Forms Over The Skies In Haridwar; WATCH Viral Video