Will Two Typhoons Collide? What is the Fujiwhara Effect?
TyphoonSays·防御问答 · Typhoon knowledge · 更新 at 2026-07-18
Will Two Typhoons Really "Crash" into Each Other?
During the summer and autumn seasons in the Northwest Pacific, it is not uncommon for two or even multiple typhoons to be active simultaneously. Many people wonder: will they crash into each other directly like bumper cars? In reality, physical "hard collisions" between typhoons are extremely rare. This is because a typhoon is essentially a massive low-pressure cyclonic system, often hundreds of kilometers in diameter. When two typhoons approach each other, complex interactions occur between their airflows and pressure fields, causing their paths to deflect, rotate, or merge, rather than simply colliding in a straight line. This phenomenon has a specific name in meteorology—the Fujiwhara Effect. Simply put, dual typhoons are more like partners performing a complex "pas de deux," restraining and influencing each other. They may eventually dissipate separately, or one may absorb the other, but they will never collide like solid objects.
What is the Fujiwhara Effect?
The Fujiwhara Effect was proposed by Japanese meteorologist Sakuhei Fujiwhara in the 1920s. It refers to the phenomenon where two tropical cyclones in close proximity rotate counter-clockwise around a central point on the line connecting them. You can imagine these two typhoons as two dancers holding hands and spinning on an ice rink. The specific manifestations usually include the following scenarios:
- Mutual Rotation: If the two typhoons are of similar intensity, they will rotate around a common center point, making their paths difficult to predict.
- One Strong, One Weak: If there is a significant disparity in intensity, the stronger typhoon will dominate the situation. The weaker typhoon may rotate around the stronger one, or even be absorbed and merged by it, potentially causing the stronger typhoon to intensify further.
- Repulsion and Separation: Under certain atmospheric circulation conditions, the two may repel each other and move in opposite directions.
This effect significantly increases the difficulty of typhoon path forecasting, as forecasters must account not only for the influence of large-scale environmental airflow but also for the interference caused by the other typhoon. Therefore, during periods of dual typhoon activity, path forecast errors by meteorological departments may be slightly larger than during single-typhoon periods. The public should pay close attention to the latest forecasts.
How Should We Respond to Dual Typhoons?
When two typhoons coexist, weather conditions often become more complex and variable. The wind and rain brought by one typhoon may be amplified by the outer cloud bands of the other, leading to longer-lasting and more widespread rainfall. For ordinary residents, the focus of defense should be on "preparing for changes" and "avoiding risks."
First, do not rely solely on experience to judge when the wind and rain will end. Dual typhoons may cause weather conditions to intensify again after an "intermission." Do not venture out rashly when the storm temporarily subsides. Second, pay attention to official warning signals. According to the national standard for tropical cyclone grades issued by the China Meteorological Administration (CMA), typhoons are classified into five levels: tropical storm, severe tropical storm, typhoon, severe typhoon, and super typhoon. When a yellow typhoon warning or higher is issued, it is recommended to reduce outdoor activities; if an orange or red warning is issued, some areas may implement measures such as school and work suspensions. Please note that standards may vary by location, so refer to announcements from local governments.
Finally, check whether windows and doors at home are secure, clear clutter from balconies, and stock up on necessary drinking water and food. In complex meteorological conditions, maintaining access to information is crucial. Real-time typhoon tracks can be queried at TyphoonSays (taifengshuo.com)
This article is typhoonsay's original copy content, and the local policy standards are based on the local government's latest release.