Five people were injured last month when an American Airlines flight encountered unexpected turbulence en route from Miami to Raleigh-Durham.
Summer turbulence is generally more predictable because it is often linked to storm activity. However, it is important to note that turbulence, in general, is becoming increasingly frequent and severe regardless of the season.
Paul Williams, a professor of atmospheric science at the University of Reading in the U.K., studies turbulence and told USA TODAY that the data on the trends for bumpy flights is clear.
“We have very strong evidence now in many published studies that turbulence is stronger today than it was in 1979,” when satellite observance of turbulence began. Williams said severe clear air turbulence is 41% more common over the U.S. now than it was in 1979.
In general, there are three major causes of turbulence, but their frequency fluctuates throughout the year.
According to Williams, clear air turbulence typically peaks in the winter when the jet stream is strongest. In contrast, convective turbulence is most likely to occur during the summer, thanks in large part to summer storms.
“You can see it from the cockpit window, which certainly helps,” Williams said. “It’s visible both to the naked eye and to the onboard electronics, and that certainly helps. You still have to fly quite far away from a storm before the turbulence declines to its background level.”
Current Federal Aviation Administration guidance recommends that pilots fly at least 20 miles from storms to avoid the most severe turbulence caused by most weather systems. Still, Williams said that evidence increasingly shows that severe turbulence can occur even farther from a storm’s center.
Most experts agree that the best way to stay safe in turbulence is to keep your seatbelt fastened at all times when seated. Especially when it comes to clear air turbulence, which can be harder for pilots to detect and for airline weather forecasters to predict, there may not be enough time for the seatbelt sign to activate before the bumps begin.
“One thing (regulators) could do is say: ‘whenever you’re seated, you should have your seatbelt fastened.’ That would save hospital visits and it would even save lives, potentially,” Williams said. “Just about everybody who is injured by turbulence is someone who was not seatbelted during the turbulence.”
As the hottest part of the summer and its associated severe weather approaches, it’s a good idea to think about taking early flights whenever possible.
“Convection turbulence is at the hottest part of the day in the early afternoon, so that would be a good time to avoid if you don’t have convective turbulence,” Williams said.
In general, delays caused by weather and other factors tend to accumulate throughout the day in the aviation system, so this tactic has the added benefit of potentially helping your trip stay on schedule as well.
Still, Williams said, the very first flight of the day could be marginally more likely to encounter turbulence than later flights, because flight planners often rely on real-time reports from pilots to identify turbulence along airplane routes, and the first flights of the day don’t have such data available to them.
Zach Wichter is a travel reporter and writes the Cruising Altitude column for USA TODAY. He is based in New York and you can reach him at zwichter@usatoday.com.
