Print Friendly, PDF & Email

The Fujiwhara effect

Facts for Prelims (FFP)


Source: IE

 Context: The western coast of the United States recently experienced Hurricane Hilary, which transformed into a sub-tropical storm upon reaching the US.

  • This event led to the National Hurricane Centre (NHC) issuing its inaugural tropical storm watch for certain areas of Southern California.
  • California had an exceptionally wet winter with multiple ‘atmospheric river’ storms, and the area also witnessed the intriguing phenomenon of the ‘Fujiwhara effect’ during one of these storms, where two low-pressure areas interacted in an unexpected manner.


About The Fujiwhara effect:

  • The “Fujiwhara effect,” where two cyclones (or hurricanes) spinning in the same direction interact in a dance-like manner around a common centre. If one cyclone is stronger, it can absorb the weaker one.
  • When of similar strength, they might merge or rotate around each other. In some rare instances, the two cyclones could merge into a mega-cyclone with significant destructive potential.
  • The Fujiwhara effect was first described by Japanese meteorologist Sakuhei Fujiwhara in 1921.