What is it Bomb Cyclone?
Explosive cyclogenesis, also known as bomb cyclone, weather bomb, metrological bomb or bombogenesis, is an extra-tropical mid-latitudinal cyclone formed due to an extreme drop in atmospheric pressure at the centre. The atmospheric pressure drops by at least 24 millibars in 24 hours.
According to National Oceanic and Atmospheric Administration’s website, a bomb cyclone occurs when a “cold air mass collides with a warm air mass.”
Basic facts about bomb cyclones-
- They have cold air and cold air fronts.
- They form under strong upper level winds.
- They occur during the winter.
- The mainly form in the Northwest Pacific and Northwest Atlantic.
Development of Explosive cyclogenesis-
The development or formation is though the following stages–
- Dry air flows into an area of low pressure.
- Causes→ depression within the storm
- Rise rapidly and increase its rotation → deepening the pressure
- Storm becomes more powerful.
Factors affecting Bomb Cyclone-
- Vorticity Maxima– explosive cyclogenesis events tend to occur in association with large amplitude 500 hPa vorticity maxima.
- Baroclinicty– increased baroclinicty helped to strengthen both the jetstream and the vorticity advection, which helped to further deepen and thus strengthen the bomb cyclone.
- Jet Stream and topography– while the jetstream helps to provide the instability needed for a bomb cyclone to develop, it’s the topography of the East Coast that acts as a focusing and triggering mechanism.
Region of occurrence-
The four most active regions where extra-tropical explosive cyclogenesis occurs in the world are-
- the Northwest Pacific,
- the North Atlantic,
- the Southwest Pacific, and
- the South Atlantic
Impact of Bomb Cyclone-
- Violent strong winds– wind speed is quiet strong and severe.
- Blizzard/ Heavy Snowfall– at times the snowfall may be up to 1 foot.
- Flood– the rainfall is with very high intensity causing severe floods.
- Damage to Flora and Fauna– causes uprooting of trees, habitat loss for animals etc.
- Damage to infrastructure– collapsing of buildings and other public infrastructures.
- Social damage– loss of residence and lives of humans.
- Economic losses– economic loss is too large to be estimated.
- Bomb cyclones draw air from Polar Regions after they leave– hence severe cold winds enters the region.
A warming world has increased the possibility of the occurrence of such intense storms, though scientists say that directly attributing this storm to climate change would not be possible at this point in time.
Even though only a minority of the bombs become so strong, some have caused significant damage.
UPSC Mains Question-
Describe the phenomenon of Explosive Cyclogenesis. What are its characteristics? And discuss its impact on the region.