What is a Bow Echo?

A powerful storm that struck Delhi on 25 May exhibited an unusual crescent-shaped structure on India Meteorological Department (IMD) radar imagery — technically termed a “Bow Echo.”

What is a Bow Echo?

• A Bow Echo is a radar signature of a fast-moving, curved line of thunderstorms, resembling an archer’s bow.
• Typically linked to severe windstorms, it is often a sign of dangerous straight-line winds.
• Size & Duration:
  • Can span 20 to 100 km in length.
  • Lasts 3 to 6 hours.
• First described in the 1970s by meteorologist Ted Fujita, who also created the Fujita Scale for tornado classification.

How It Forms:

1. Rain-cooled air from thunderstorms descends and spreads outward along the ground.
2. This creates a gust front, where the cool air meets warm, moist surface air.
3. The gust front lifts warm air, triggering new thunderstorm cells ahead of the line.
4. These new storms create more rain-cooled air, reinforcing the gust front and sustaining the system.

Why It Matters:

• Bow echoes can cause widespread wind damage, even without tornadoes.
• Tracking them helps meteorologists predict and warn about severe weather events, including microbursts and damaging straight-line winds.

(Source: IE)