Bomb Cyclone: Meteorological Extremes

In the News: A massive "bomb cyclone" struck the Northern US and Lake Superior region in late December 2025, causing pressure to drop to 945 mbar and triggering blizzard conditions.

Geophysical Mechanics

• Bombogenesis: The defining characteristic is a rapid pressure drop of at least 24 millibars in 24 hours. This creates an extreme "pressure gradient," resulting in hurricane-force winds.
• The Catalyst: It occurs when a Cold Arctic air mass (High Pressure) collides with a Warm Maritime air mass (Low Pressure), usually over the North Atlantic or Great Lakes.

UPSC Geography Linkage

• Winter Cyclones: Unlike tropical cyclones (driven by warm water), bomb cyclones are extratropical and are driven by temperature contrasts (baroclinic instability).
• Impact: They disrupt the Polar Vortex, pushing frigid air much further south than usual.