Bomb cyclones explained: What are they and what makes them so dangerous?

Dangerous weather events known as bomb cyclones are characterized by their rapid intensification and the potential to cause significant damage. These systems, forming primarily in mid-latitude regions between the Earth’s tropical and polar regions, bring severe winds, heavy rainfall, snowfall, and sometimes extremely cold temperatures. According to meteorologists, although they may exhibit hurricane-like characteristics, bomb cyclones are fundamentally different.

What defines a bomb cyclone?

A bomb cyclone, also called explosive cyclogenesis or bombogenesis, is a low-pressure system that rapidly intensifies. It forms when atmospheric pressure drops by at least 24 millibars within a 24-hour period. Such systems typically develop over the oceans during the winter months, lasting about a week. Winds often reach hurricane strength, accompanied by large amounts of rainfall. Bomb cyclones tend to peak in intensity four to five days before tapering off, according to what John Martin, a professor at the University of Wisconsin-Madison, told Reuters.

How do bomb cyclones develop?

The ideal conditions for bomb cyclone formation involve specific interactions between surface-level and upper-atmospheric weather systems. The jet stream – a high-altitude band of powerful winds – plays an important role. Atmospheric disturbances occurring in the troposphere, about 5–8 km above the ground, often precede the development of these storms. Professor Martin said warm sea surfaces are another important factor, with many intense bomb cyclones originating in such areas. The latent heat energy released during the condensation and freezing processes further intensifies these storms.

where and when they occur

Bomb cyclones are most common in hurricane-prone areas on the eastern coasts of continents, where warm ocean currents are present. Notable examples are the Gulf Stream near North America and the Kuroshio Current near Japan. These systems form primarily during the colder months, from November to March in the Northern Hemisphere and from May to August in the Southern Hemisphere.

Are bomb cyclones becoming more frequent?

The relationship between climate change and bomb cyclone activity continues to be investigated. Professor Martin highlighted in a statement that increasing water vapor in the atmosphere due to global warming could increase the latent heat dynamics of storms. However, uneven warming across latitudes may balance this effect. The implications of the cyclone’s strength and frequency continue to be studied.