SCIENCE LAB SPECIAL : BUCKLE YOUR SEATBELTS

Study suggests wider detours to avoid air turbulence : Rattled nerves and spilled drinks are the most common outcomes of a choppy flight, but intense air turbulence can also cause bodily harm.

And while one well-known cause of air turbulence is thunderstorms, it's poorly understood how far from a tempest shaky conditions are likely to persist.

To answer that question, researchers recently analyzed millions of measurements of air turbulence collected by commercial aircraft.

The team found that a heightened risk of jarring flight extended more than 55 miles [ 89 kilometers ] from a thunderstorm, which is roughly three times the storm-avoidance distance currently recommended by the Federal Aviation Administration.

These findings, published in The Bulletin of the American Meteorological Society, could inform new guidelines for storm avoidance, the researchers suggest.

Pilots and dispatch crews on the ground have long kept an eye trained on the weather. '' The links between meteorology and aviation go way, way back,'' said Stacey Hitchcock, an atmospheric scientist at the University of Oklahoma in Norman.

Thunderstorms are of particular concern to pilots. '' You get really rapid changes in vertical and horizontal motion over short distances,'' Dr. Hitchcock said.

Those chaotic motions - which can also be caused by jet stream winds and air moving around obstacles like mountains - can cause aircraft to go up and down, creating the tumultuous sensation that's all too familiar to many fliers.

Dr. Hitchcock and her collaborators analyzed roughly 200 million such measurements made in United States airspace from 2000 to 2017.

The team focused on the eddy dissipation rate, a metric released in the vertical acceleration experienced by a plane and its occupants. [ Katherine Kornei ]