Syllabus 

GS 1: Important Geophysical phenomena such as earthquakes, tsunamis, Volcanic activity, cyclones, etc.

Context: Recently, a bow echo storm marked by intense winds struck Delhi, signalling severe weather and growing thunderstorm patterns in India.

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• A powerful storm struck Delhi, showing an unusual crescent or bow-shaped structure on the IMD’s weather radar.

• This shape is technically known as a "bow echo" and is often a sign of severe windstorms.

• During the storm, wind speeds reached up to 100 kmph in Delhi.

Bow Echo

• A bow echo is a curved, bow-shaped radar signature of a squall line, indicating a line of thunderstorms with strong winds and potentially tornadoes.

• A "squall line" refers to a linearly oriented zone of convection (i.e., thunderstorms). 

• Squall lines are common, especially during the spring when the atmosphere is most "dynamic."

• A "bow echo" or "bowing line segment" is an arched/bowed out line of thunderstorms, sometimes embedded within a squall line.

• The term "bow echo" is based on how bands of rain showers or thunderstorms "bow out" when the storm's strong winds reach the surface and spread horizontally.

• These can be embedded within larger squall lines.

• Size: 20 km to 100 km wide

• Duration: 3 to 6 hours

• The term was first coined in the 1970s by meteorologist Ted Fujita, known for the Fujita scale used for classifying tornadoes.