United States

Chaplain Leslie L. Grounds, center, gives an invocation during a ceremony dedicating a site to the Aug. 2, 1985 Delta Airlines Flight 191, Monday, Aug. 2, 2010 at Dallas Fort Worth International Airport in Grapevine, Texas. (AP Photo/Cody Duty)

Today marks the 27th anniversary of the crash of Delta Flight 191 - one of the most infamous weather-related plane crashes that led to the understanding of how microbursts impact aviation and the first installations of Doppler Weather Radars at airports in the U.S.

The passenger jet en route to Los Angeles crashed near Dallas, killing more than 130 people on Aug. 2, 1985.

Delta Flight 191 was scheduled to make a layover at the Dallas-Forth Worth International Airport. The airplane encountered strong downburst winds from a thunderstorm, lost control in the erratic winds, clipped a water tank and exploded short of the runway.

Twenty-six people survived.

The crash was attributed to a weather phenomenon known as a microburst. When some thunderstorms collapse, it causes a sudden violent downward rush of air through the storm's core. The flow has nowhere to go but out once it reaches the ground. Thunderstorm downbursts are a serious hazard to flights.

If a plane flies across the base of a thunderstorm and encounters the tailwind side of a downburst, meaning the outflow winds are flowing in the direction of the plane's movement, the lifting forces on the wings of the plane are dramatically reduced. This can cause planes to plummet. Especially if a plane is at a low altitude as it may be for landing, there is little time for recovery.

Expert Senior Meteorologist Henry Margusity said he remembers working the day of the crash.

"It was a really hot day," he said. "It was kind of a heat wave going on, and that was the only thunderstorm in the area at the time."

The devastating abilities of microbursts were not known at the time of the Flight 191 tragedy, though it had been theorized by Dr. Ted Fujita.

Fujita investigated the crash and found evidence supporting the idea that a downburst or microburst could have caused the Lockheed L-1011's crash.

This disaster led to the installation of Terminal Doppler Weather Radars at 44 airports across the country - all installed with the specific purpose of detecting wind shears, including microbursts. Moreover, the Federal Aviation Administration established training for pilots that taught them to avoid downbursts and how to get out of them if they got caught up in one.

The Delta crash also led to changes at the National Weather Service including co-locating the warning responsibility and radar.

One other crash has since been attributed to microburst action - USAir 1016 in Charlotte in 1994.