How the Fujiwhara Effect forces hurricanes to dance
Two hurricanes can dance around one another when they invade each other’s personal space
What happens when two hurricanes track too close together?
The storms won’t collide in a cinematic climax. Instead, they’ll start dancing around one another in a delicate atmospheric tango thanks to the Fujiwhara Effect.
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The Fujiwhara Effect is rare and spectacular
The Fujiwhara Effect occurs when two storms are close enough together that they begin to interact with one another.
Named for the Japanese meteorologist who first described the phenomenon in the early 1900s, the Fujiwhara Effect is spectacular to watch unfold.
One tropical cyclone will be able to feel the influence of a nearby storm once they’re about 1,400 km apart. From there, three different scenarios can unfold.
The first scenario can see the two storms begin to rotate around the stronger storm. These systems can lock into a dramatic orbit, like two dancers holding hands while they twirl in unison, if they’re as close as 650 km apart.
If one of the cyclones outweighs the other in size and strength, the weaker storm can even dissipate and absorb into the dominant system. This can cause the ‘winning’ system to grow even larger.
If the two storms are roughly equal in strength, and they’re not terribly close together, the Fujiwhara Effect can force them to deflect away from each other, sort of like two magnets repelling one another. This scenario can cause serious complications when one of the storms is close to land.
There are a handful of real-world scenarios in which the Fujiwhara Effect has played a significant role in the track of storms as they churn across the ocean.
We saw the phenomenon play out in July 2017 when Hurricane Hilary and Hurricane Irwin tracked near each other in the eastern Pacific Ocean.
Hilary was the stronger storm as it moved northwest, while nearby Irwin found itself weaker as it headed toward the west. Hilary caught up to Irwin from behind, causing the weaker storm to abruptly stop in its tracks before changing course toward the northwest for the remainder of its short life.
Scientists still aren’t sure exactly how the Fujiwhara Effect works; some theorize that it’s a complex interaction between each storm’s wind field. The dance between nearby storms can throw a wrench in the forecast by ratcheting up uncertainty—especially when these storms are near land.