What is the "Fujiwhara effect"?

The Fujiwhara effect is a rare phenomenon where two tropical storms or hurricanes get close enough to each other to interact, causing them to either merge or spin around a common center.

How strong is Hurricane Humberto?

Hurricane Humberto has reached Category 5 strength, making it a major and powerful hurricane. However, it has since fluctuated back down slightly in intensity.

What is the threat from Tropical Storm Imelda?

Tropical Storm Imelda is developing nearby and could potentially interact with Hurricane Humberto. If this happens, it could produce heavy rainfall and flooding threats for the southeastern United States, including Florida and the Carolinas.

Home / Weather / Rare "Fujiwhara Effect" Threatens Collision of Powerful Hurricanes

Rare "Fujiwhara Effect" Threatens Collision of Powerful Hurricanes

29 Sep

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Summary

Hurricane Humberto, a major Category 5 storm, may interact with Tropical Storm Imelda
Fujiwhara effect could cause the storms to merge or spin around each other
Forecasters warn of heavy rainfall and flooding threats to the southeastern U.S.

Rare "Fujiwhara Effect" Threatens Collision of Powerful Hurricanes

As of September 29th, 2025, the Atlantic hurricane season has intensified with the emergence of two powerful storm systems. Hurricane Humberto, a major Category 5 hurricane, is currently swirling over open waters north of the Caribbean. Meanwhile, a second system, Tropical Storm Imelda, has developed nearby in the western Atlantic.

Meteorologists are closely monitoring the potential for these two storms to interact in a rare phenomenon known as the "Fujiwhara effect." This occurs when two tropical systems get close enough to each other to reach a common point, causing them to either merge or spin around a newly formed, shared center. The outcome depends on the relative strength and size of the storms involved.