Whenever a large storm front develops somewhere in the world, air travel gets a bit more complicated than usual. Air routes are closed, holding patterns are established, flights get delayed and some are unfortunately cancelled. Thunderstorms present a massive problem if they are standing between you are your destination, even if the area they affect is relatively small.

Typhoons/hurricanes, however, are a beast of a whole other nature. Typhoons/hurricanes are massive, spanning hundreds or thousands of miles and affecting flights on a regional scale. While a thunderstorm may develop and move through an area quickly, the effects of a typhoon/hurricane linger for days. Airports directly affected by a typhoon/hurricane will close for obvious reasons, often for days. Airport closures due to thunderstorms tend to be much shorter. 

But what happens to all the flights that need to travel through a thunderstorm or a typhoon/hurricane? First, airlines treat thunderstorms differently from typhoons/hurricanes for flight-planning purposes.

The structure of a thunderstorm is drastically different from that of a typhoon/hurricane. Thunderstorms and typhoons/hurricanes are both convective in nature, but in different ways. Thunderstorms create massive cloud structures with tops that can reach over 60,000 feet, well above the cruising altitude of commercial airplanes, while typhoons/hurricanes typically do not. Using their onboard weather radar or guidance from air traffic controllers, pilots will always navigate around thunderstorms — or simply turn around.

Typhoons/hurricanes, however, are not always as disruptive to flights as a thunderstorm can be. “As far as aviation goes, most tropical systems and typhoons/hurricanes are, generally, not as tall as traditional thunderstorms,” said meteorologist and pilot James Aydelott. “The tallest convection in a tropical cyclone is usually clustered around the central core of rotation, whether that’s just a low pressure, or in a typhoon/hurricane, an eye,” he explained. This enables airlines to file flight plans that actually operate over parts of a typhoon/hurricane.

For obvious reasons, no commercial aircraft is ever going to penetrate the eyewall of a typhoon/hurricane. As you get further away from the eye of the typhoon/hurricane, though, flight conditions become more and more manageable. Unlike with many thunderstorms, flights can safely navigate over the top of a typhoon/hurricane or tropical storm with little impact.

While flights above typhoons/hurricanes can be perfectly safe, they do require a bit of extra planning and attention to detail. “If you needed a diversion for maintenance or medical, your options are a bit more limited, but from a cruise altitude, you have a lot of airports even further on the storm’s fringe to divert toward,” said Aydelott. While many flights will simply opt to travel around the storm, doing so is not actually required.

As weather predicting and sensing technology improves over time, and as pilots are able to receive more and more real-time weather data while in flight, navigating around and over storms can become more commonplace. For now, most flights will be routed around typhoons/hurricanes while a few will opt to take a bit of a shortcut right over the top.