How does turbulence affect Western Pa. flights?

As Lu Ann Walter waited in baggage claim at Pittsburgh International Airport for her daughter and grandchildren to arrive from Alaska, she wasn’t concerned about the dangers of turbulence on their more than six-hour flight.

“I think she’s smart enough to wear a seatbelt,” said Walter, of Leeper.

The potential dangers of air turbulence made international news on May 21, when a flight from London to Singapore encountered extreme turbulence over Myanmar’s Irrawaddy Basin. The sudden drop in altitude resulted in the death of one passenger and injuries to 71.

In the wake of the incident, travel experts have repeated the advice that air passengers should keep their seatbelts on at all times during flight. Locally, meteorologists have noted that the atmosphere in Pennsylvania generally poses low risks for turbulence, making Pittsburgh a safe area to fly in and out of.

William Syrett, an associate professor of meteorology at Penn State, said Pennsylvania generally experiences less intense thunderstorms than tropical regions like Southeast Asia.

“Turbulence is simply an area of rising and sinking air in close proximity,” Syrett said.

There are two environmental causes of turbulence.

The first cause comes from thunderstorms, said Carnegie Mellon University professor and meteorologist Neil Donahue.

He called the area around Myanmar “probably the most intense in the world for tropical thunderstorms.” The flight to Singapore was “definitely going through a hotspot.”

While less common, clear air turbulence is often a more spontaneous cause for turbulence because of wind shear.

Wind shear occurs when various masses of air, which are different temperatures, begin to travel at different speeds causing strain in the air.

The feeling people experience during turbulence is caused by a plane moving up and down as sections of air rise while surrounding ones sink.

Pittsburgh’s thunderstorms don’t often get as tall as the storms in Southeast Asia and are less likely to become as big of a problem, Donahue said.

“If there’s a thunderstorm here around Pittsburgh they avoid it,” he said. “Planes don’t just fly into thunderstorms.”

Mike Kennedy, a National Weather Service Pittsburgh meteorologist, said he has not seen an increase in reports of severe turbulence during flights.

“There’s no threat of injury or anything happening to the plane,” Kennedy said. “It’s very common.”

Weather monitoring detection is a great help during warmer months when thunderstorms peak, Syrett said.

“Accidents are rare, but they’re more rare now,” Syrett said. “I would trust the system.”

The major concern with areas of clear air turbulence is that it generally does not appear on the radar.

Due to the lack of visibility and visual clues, Donahue said, these areas can be difficult for pilots to anticipate and navigate.

Pilots can use the forecasts as a guide for their flight plans, but often make adjustments as other plans report areas of “bumpy air.”

“While pilots can take steps to ease most turbulence, it can often be unavoidable or unexpected, but planes are designed to safely withstand the potential impacts,” the Air Line Pilots Association union said in a statement.

Kennedy said he does not think the possibility of turbulence should impact people’s decision to fly.

“It’s very normal,” he said. “There is nothing you can do about it.”