No Hurricane Has Ever Crossed the Equator. Here's Why

Tropical weather season is in full swing in both the Atlantic and Pacific basins. But one place that you will never see a hurricane is right near the equator. Why is that? Read on for the scientific explanation behind this fact.

How the Coriolis Force Impacts the Track of Tropical Weather Features

Although a handful of tropical weather systems have come close to crossing the equator throughout history, a named storm has never made this journey. The answer for this phenomenon lies in what is known as the Coriolis force.

This force inherently deflects winds to the right in the Northern Hemisphere while sending winds to the left in the Southern Hemisphere. Most people recognize the force as the atmospheric element on a map that generates the swirl you see in tropical weather events. The circular movement is counterclockwise in the Northern Hemisphere and clockwise in storms spinning in the Southern Hemisphere.

The Coriolis force is at zero right at the equator. It is this force that prevents tropical weather features from crossing over the equator and moving between hemispheres.

Most tropical weather systems remain north of the equator at a position of at least five degrees north latitude. Conversely, storms remain to the south at 5 degrees south latitude.

Notable Storms in History That Approached the Equator

The closest storm to approach the equator happened in December of 2001 when Typhoon Vamei spun up in the western Pacific Ocean. Vamei came within 100 miles of the equator after it formed at just 1.4 degrees North latitude.

Going back in time a bit further, an unnamed tropical depression formed at 0.5 degrees latitude in December of 1973. The China Meteorological Administration (CMA) confirmed that the feature evolved into a tropical storm when it reached a position of 0.7 degrees latitude.

However, the CMA uses a different parameter than the National Oceanic and Atmospheric Administration (NOAA) in the U.S. Thus, while the CMA said that it was named a tropical storm at this position, NOAA said that the feature did not have high enough wind speeds to constitute a tropical storm. The storm did not hit that designation until it had traveled north of 10 degrees north latitude.

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