Thunderstorms and sudden, unpredictable wind storms called derechos are becoming a bigger threat to your summer travel plans.
In mid-May, a derecho swept across the Gulf Coast, causing damage in Texas and Louisiana and halting air travel. Over May 16-17, in particular, there were dozens of flight cancellations and nearly 400 delays at Houston’s two main airports, according to data from FlightAware.
These storms occur with little or no notice, surprising passengers who checked the weather report and thought they were all clear. The storms can flip over small planes with their strong winds and halt airport operations entirely. They are most common in May, June and July.
The sheer size of most derechos means that multiple hubs could shut down operations at the same time, grounding hundreds of flights, says Renny Vandewege, a meteorologist and general manager for weather and climate intelligence at DTN, a global data, analytics and technology company.
And derechos aren’t the only heightened risk to your travel plans. This year has brought many strong thunderstorms across the U.S., meteorologists say. A stronger jet stream is developing across the country, thanks to a change in the climate pattern known as El Niño. That wind helps lift moisture higher into the atmosphere, which can cause more intense storms to develop.
States across the central and eastern time zones could bear the brunt of those extra storms. That means more delays and cancellations—and more potential turbulence for the flights that do take off.
What are derechos?
Derechos are a type of straight-line wind storm—their winds don’t rotate like a tornado does. They often pack hurricane-force winds, and unlike other wind storms, derechos stretch for hundreds of miles, moving rapidly.
“The thing about derechos that is unique is just how broad and wide an area of wind it creates,” Vandewege says.
Nearly four years ago, a derecho swept from Nebraska to Ohio, destroying thousands of homes and businesses across the Midwest. A 2012 derecho left millions without power.
Jim Szczesniak, aviation director for the Houston Airport System, says the Houston area’s two major airports had only 60 minutes to 90 minutes to prepare for the incoming derecho in May. Those preparations include securing any loose items around the airport that could become airborne in high winds and shutting down the Skyway people mover at George Bush Intercontinental Airport. Air-traffic-control facilities must undergo similar preparations ahead of storms, the Federal Aviation Administration says.
The impact to air travel isn’t limited to ground operations. Besides stretching for miles, derechos tend to reach quite high into the atmosphere, says Jennifer Stroozas, the warning coordination meteorologist for the Aviation Weather Center.
“There’s no squeezing through them or going over the top of them,” she says. Consequently, aircraft must circumnavigate them, extending the duration of flights and potentially causing a domino effect of other delays or cancellations.
How often will hurricanes hit?
Meteorologists are also forecasting a busier thunderstorm and hurricane season than usual. While the damage from named hurricanes might last for years, the damage from quicker-developing thunderstorms can add up. In 2023, these types of storms accounted for about two-thirds of all insured natural hazard-related losses, according to insurance brokerage Gallagher Re.
More severe storms will come, meteorologists say, because El Niño is weakening. This will lead to the development of derechos and other forms of severe weather.
Water temperatures are above normal in the Gulf of Mexico and the Caribbean, Vandewege says. As that water evaporates, it rises up into the atmosphere. The National Oceanic and Atmospheric Administration is forecasting a range of 17 to 25 named storms during the 2024 Atlantic hurricane season.
The agency expects roughly half of those storms to reach hurricane strength, including between four and seven major hurricanes with wind speeds of 111 miles an hour or higher. Three major hurricanes emerged during the same period in 2023.
Last week, a wave of thunderstorms blew across Texas, damaging Dallas and Houston. One of the storms packed winds powerful enough to push an American Airlines jet away from its gate. The storm system delayed or caused the cancellation of hundreds of flights out of Texas airports, according to FlightAware.
How can you prepare?
Prepping involves more than just checking forecasts.
Stroozas suggests using websites that track flights to get a sense of the normal routes flights take to arrive at their destination, as well as where the given aircraft tends to come from.
Closer to their flight, fliers can check along those routes on meteorology websites, including those managed by the government-run Aviation Weather Center and the Storm Prediction Center, to gauge the chances of bad weather. The FAA also issues a daily air-traffic report that outlines potential weather impacts.
“If you have a big line of thunderstorms throughout the central part of the country, flights can’t go right through that line. They have to find a way around,” Stroozas says.