Cyclone 'Dana' Impact on Bihar

• 24 Oct 2024

Why in News?

Recently, Cyclone 'Dana' has caused significant changes in the weather pattern across Bihar, leading to heavy rainfall warnings for several districts.

Key Points

• Affected Districts: Patna, Gaya, and other nearby regions are likely to experience significant rainfall.
  • The India Meteorological Department (IMD) has issued a yellow alert, warning residents to prepare for potential flooding.
  • Cyclone Dana is also influencing weather conditions in neighboring states like Jharkhand and West Bengal.
• Colour- Coded Weather Warning:
  • It is issued by the IMD whose objective is to alert people ahead of severe or hazardous weather which has the potential to cause damage, widespread disruption or danger to life.
  • The IMD uses 4 color codes are:
    • Green (All is well): No advisory is issued.
    • Yellow (Be Aware): Yellow indicates severely bad weather spanning across several days. It also suggests that the weather could change for the worse, causing disruption in day-to-day activities.
    • Orange/Amber (Be prepared): The orange alert is issued as a warning of extremely bad weather with the potential of disruption in commute with road and rail closures, and interruption of power supply.
    • Red (Take Action): When the extremely bad weather conditions are certainly going to disrupt travel and power and have significant risk to life, the red alert is issued.
  • These alerts are universal in nature and are also issued during floods, depending on the amount of water rising above land/in a river as a result of torrential rainfall.
    • For instance, when the water in a river is ‘above normal’ level, or between the ‘warning’ and ‘danger’ levels, a yellow alert is issued.

Cyclone

• Cyclones are rapid inward air circulation around a low-pressure area. The air circulates in an anticlockwise direction in the Northern hemisphere and clockwise in the Southern hemisphere.
• Cyclones are usually accompanied by violent storms and bad weather.
• The word Cyclone is derived from the Greek word Cyclos meaning the coils of a snake. It was coined by Henry Peddington because the tropical storms in the Bay of Bengal and the Arabian Sea appear like coiled serpents of the sea.
• There are two types of cyclones:
  • Tropical cyclones; and
  • Extra Tropical cyclones (also called Temperate cyclones or middle latitude cyclones or Frontal cyclones or Wave Cyclones).
• The World Meteorological Organisation uses the term 'Tropical Cyclone’ to cover weather systems in which winds exceed ‘Gale Force’ (minimum of 63 km per hour).
  • Tropical cyclones develop in the region between the Tropics of Capricorn and Cancer. They are large-scale weather systems developing over tropical or subtropical waters, where they get organized into surface wind circulation.
• Extra tropical cyclones occur in temperate zones and high latitude regions, though they are known to originate in the Polar Regions.