It goes without saying that weather is a determining factor when planning a flight. Some of the most common weather phenomena are minor or easily avoidable; others, however, must be taken into account and can lead to a rerouting or flight cancellation. Today we’ll learn a little more about how a low-pressure system, known in Spain as a borrasca, affects airplanes; how pilots detect them; and why they are given names.
What Exactly Is a Low-Pressure System?
Technically this is an area where the pressure is lower than that of the surrounding air. It is the opposite of an anticyclone, where the atmospheric pressure is high. To put it in a much simpler way, a borrasca is equivalent to what we commonly call a storm or bad weather: more or less strong winds, rain, low temperatures, hail, snow, and so forth.
A storm causes the air to cool, which leads to condensation and the subsequent formation of clouds. This is why precipitation is common, as the perfect conditions for it occur during a storm.
But are all storms the same? Of course not. Like any weather phenomenon, there are different degrees. The strongest are known as high-impact storms. We’ll come back to them later.
How Does a Storm Affect Flight Planning?
We’ve all been concerned about the weather at some point, especially if we have to travel. This is no different from a pilot planning their next flight. The weather determines the route we’re going to take – or whether or not we can even begin it.
Based on this, can airplanes fly through storms? Absolutely. To give you an idea, airplanes are currently equipped to fly even through much more extreme weather events, such as a hurricane. But for passengers’ comfort and peace of mind, the first option is always to avoid them.
Tools That Pilots and Airplanes Have at Their Disposal to Deal with Storms
As we already know, meteorology plays a huge role in putting together a flight plan. Among the tools pilots have at their disposal is what is known as a weather chart, a service provided in our country by Aemet (Spanish Agency for Meteorological Services). Each chart is valid for six hours, so that information on possible weather changes is as accurate as possible. This way the flight plan can be executed with the most up-to-date information, and a route can be designed that avoids crossing a storm.
Another instrument that allows a pilot to detect areas with adverse conditions is weather radar, making it unlikely that a flight will have to fly through a storm. But what if it can´t be avoided? We’ve already mentioned that an airplane today is prepared to cross much more significant phenomena than an area of heavy cloud cover. The point is that, while crossing, visibility is reduced, and you have to resort to another of the tools available to airplanes: IFR (instrument flight rules).
IMC and IFR
IMC (instrument meteorological conditions) or instrument flight rules are the terms used in aeronautics to refer to situations in which an adverse phenomenon forces a pilot to fly under instrument flight rules (IFR), since in these low-visibility circumstances, visual references are invalid. With this small modification, planes that need to fly through storms can do so without any problem.
Why Do Storms Have Names?
You’ve probably seen meteorologists or journalists refer to a storm by a masculine or feminine name more than once. Are all storms named? No, not at all. A storm is an all-too-frequent phenomenon, and only those that can create complicated safety situations not only for flights but also for people on the ground have their own names. These are known as high-impact storms, with strong winds and causing orange or red alerts.
Why are they assigned names? Simply because it facilitates communication. If we talk about Katrina or Filomena (the once-in-a-century snowstorm which hit Spain in January 2021), to name just two, the information provided about them is more deeply etched in the collective memory than if we talk about a “high-impact storm.” This way greater attention is paid to warnings to the public to avoid travel and, consequently, the greatest possible number of tragedies.
Criteria for Naming Storms
Most important is its potential impact. But what names are used? Male and female names alternate (one of each), in alphabetical order, avoiding letters such as Q, Y, and Z. Aemet has already named some for this 2024-2025 meteorogical year, to wit: Aitor, Berenice, Caetano, Dorothea, Enol, Floriane, Garoé, Herminia, Ivo, Jana, Konrad, Laurence, Martinho, Nuria, Olivier, Pauline, Rudiger, Salma, Timothée, Vanda, and Wolfgang.