eyewall

An eyewall is the ring of deepest, most organized convection surrounding the eye of a tropical cyclone, such as a hurricane or typhoon. It contains the cyclone’s strongest winds and heaviest rainfall and marks the boundary between the calm interior eye and the surrounding chaotic core. Inside the eye, winds are typically lighter and skies can be clear or partly cloudy, while the eyewall experiences rapid, intense weather.

The eyewall is usually a roughly circular belt that encircles the eye at varying radii. The convective activity within the eyewall is driven by the cyclone’s warm core and rapid vertical development of clouds. In some storms, multiple concentric eyewalls can form, a phenomenon known as an eyewall replacement cycle. During this cycle, a new outer eyewall can form outside the original one, temporarily weakening the cyclone as the inner eyewall decays, followed by potential reintensification when the outer eyewall contracts.

Observation and measurement of the eyewall rely on satellite imagery, radar, and reconnaissance aircraft that sample wind fields, pressure, and rainfall. Meteorologists estimate intensity with satellite techniques such as the Dvorak method and confirm details with direct measurements when available. Eyewalls drive the most damaging winds and heavy rain near landfall, and their behavior helps determine forecast intensity and warnings for tropical cyclones worldwide.