A Heat Engine Over the Ocean
A hurricane is essentially a Carnot heat engine: it extracts energy from warm ocean water at the surface and exhausts it at the cold tropopause 15 km above. The efficiency of this engine — and therefore the storm's maximum potential intensity — depends on the temperature difference between the sea surface and the outflow layer. This is why hurricanes form only over oceans warmer than 26.5°C and weaken rapidly after landfall when cut off from their energy source.
Anatomy of a Hurricane
The hurricane's structure is organized into concentric regions. The eye, typically 20-60 km across, is a calm column of descending air. Surrounding it is the eyewall, where the strongest winds and most intense rainfall occur. Spiral rainbands extend hundreds of kilometers outward, producing squalls and embedded tornadoes. The simulation above lets you see how sea-surface temperature and wind shear reshape these structures in real time.
The Saffir-Simpson Scale
The Saffir-Simpson Hurricane Wind Scale categorizes hurricanes into five levels based on sustained wind speed. Each category roughly doubles the damage potential of the one below it: a Category 4 hurricane causes 50 times more damage than a Category 1. The scale focuses on wind, but storm surge — the dome of water pushed ashore — often causes the greatest loss of life. Hurricane Katrina's 8.5-metre surge devastated the Gulf Coast despite the storm weakening to Category 3 at landfall.
Rapid Intensification and Climate
The most dangerous hurricanes are those that rapidly intensify — gaining 55+ km/h of wind speed in 24 hours — because forecast models struggle to predict this process. Rapid intensification requires deep warm ocean water, low vertical wind shear, and high mid-level humidity. Research suggests that as ocean temperatures rise, the proportion of hurricanes reaching Category 4 and 5 intensity is increasing, even if the total number of storms may not change significantly.