The Fujiwhara effect: When cyclones ‘dance’

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Last Updated27/08/2023

Recently, powerful winds tormented the Bay Area and other parts of Central and Southern California, uprooting trees and disrupting the power supply due to the Fujiwhara effect.

It was identified by a Japanese meteorologist, Sakuhei Fujiwhara.
It was observed for the first time over the western Pacific Ocean when typhoons Marie and Kathy merged in 1964.
As per the National Weather Service (NWS), when two hurricanes, spinning in the same direction, are brought close together, they begin ‘an intense dance around their common centre’- this interaction between two cyclones is called the Fujiwhara effect.

If one hurricane’s intensity overpowers the other, then the smaller one will orbit it and eventually crash into its vortex to be absorbed.
However, if two storms of similar strengths pass by each other, they may gravitate towards each other until they reach a common centre.
They will merge or merely spin each other around for a while before shooting off on their own paths.
In rare instances, the two ‘dancing’ cyclones, if they are intense enough, may merge with one another, leading to the formation of a mega cyclone capable of wreaking havoc along coastlines.
Experts have noted the rising frequency of this unusual effect, attributing it to a rapidly warming world and the subsequent heating of ocean waters.