As if 2020 wasn’t already an incredibly unique year, residents along the Atlantic coast have been presented with yet another uncommon challenge: two cyclones entering the Gulf of Mexico at the same time, an event that hasn’t happened since the 1930’s. What’s worse, many are worried that Hurricane Laura and Tropical Storm Marco may merge together, forming a single storm that’s much larger and can cause much more damage. While this is certainly a possibility, it’s important to look at the meteorological phenomenon that describes this kind of activity, and how the possibility of a “super hurricane” is not as likely as it may seem.
When two cyclones – whether they are depressions, storms, or hurricanes – come within close proximity of each other, the way they tend to behave is described as the Fujiwhara effect. Named after Sakuhei Fujiwhara, the 20th century Japanese meteorologist who first described the effect, the Fujiwhara effect occurs when two cyclones come within about 900 miles of each other. The two cyclones will begin to spin about a common point between the two systems. If one cyclone is significantly larger than the other, the smaller cyclone will likely orbit the larger one, eventually being absorbed into the larger system.
If the cyclones are approximately equal in size, the rotation around a common point will continue for some time, resulting in a few different possibilities. The first possibility is that they rotate around each other for a while and then shoot off in separate directions, their paths being altered by the interaction. Another possibility is that they will simply merge with each other. In this case, the most likely outcome is that the combined cyclone will be of approximately equal or weaker strength than either of the two systems before the merge.
That said, there is a slight chance that two merging systems will combine their strength, resulting in a “super storm” that can deal serious damage to an area. Although such an occurrence is very rare, this possibility has captivated the attention of many ever since the news of Laura and Marco occurring so closely to each other. Realistically, however, the evidence of this happening is few and far in between. As of right now, Marco is expected to dissipate while Laura continues to threaten the Texas–Louisiana coastline sometime this week.
It may be tempting to imagine a terrifying world where some mega hurricane causes cataclysmic destruction to the Southern coast, but it’s important to stay grounded in reality and prepare for the damage that Laura is likely to cause. Remember to make any emergency preparations that are necessary to stay safe, such as stocking up on supplies, creating an evacuation plan, safeguarding your residence against storm damage, and plenty of other measures.