May 3, 1999 Oklahoma Tornado Outbreak and the Bridge Creek-Moore F5

The May 3, 1999 tornado outbreak produced 72 tornadoes in Oklahoma, the largest outbreak in the state since official records began in 1950. Its most destructive storm, the Bridge Creek-Moore tornado, was rated F5 and tore a 38-mile path through Bridge Creek, Moore and southern Oklahoma City. Forty people died in Oklahoma, 36 of them in the F5 alone, and about 1,800 homes were destroyed.

What Happened on May 3, 1999

The National Weather Service office in Norman issued its first severe thunderstorm warning of the day at 4:15 p.m. Central Daylight Time for Comanche County in southwestern Oklahoma.

The first tornado warning followed at 4:47 p.m. for Comanche, Caddo and Grady counties. Four minutes later, at about 4:51 p.m., the first tornado was reported near Medicine Park. Over the next several hours, a series of supercell thunderstorms moved northeast across the state, each producing tornado after tornado.

The storm that became the Bridge Creek-Moore tornado touched down a little before 6:30 p.m. near Amber in Grady County. Researchers labeled it Tornado A9, the ninth tornado from the first supercell of the day.

The Bridge Creek-Moore F5 Tornado

Tornado A9 grew to a maximum width of 1,760 yards, a full mile, and stayed on the ground for roughly an hour and a half. Its path crossed Amber, Bridge Creek, Newcastle, southwest Oklahoma City, Moore, south Oklahoma City, Del City, Tinker Air Force Base and Midwest City.

The National Weather Service attributes 36 direct deaths and 583 injuries to this one tornado. Five more people died from illness or accidents during or shortly after it. About 1,800 homes were destroyed and roughly 2,500 more were damaged, and damage from this tornado alone came to about $1 billion. It was the costliest tornado in US history until 2011.

A Doppler on Wheels research radar scanning the storm near Bridge Creek measured winds above 300 mph. Published figures differ: the first estimate was 301 mph with a margin of about 20 mph, the Norman office’s summary cites 318 mph, and a 2021 reanalysis put the peak at 321 mph. Every version ranks among the highest wind speeds ever measured in a tornado. The storm kept its F5 rating, the top category of the Fujita scale then in use.

The First Tornado Emergency

As the F5 approached the southern Oklahoma City metro area, forecasters in Norman went beyond an ordinary tornado warning. At about 6:57 p.m., they issued a severe weather statement calling the situation a tornado emergency and telling residents to take cover immediately.

It was the first tornado emergency ever issued. Weather Service offices have since reserved the phrase for rare cases when a large, violent tornado is bearing down on a populated area. Warnings that afternoon came well ahead of the deadliest storm: the first tornado warning was issued about 90 minutes before the Bridge Creek-Moore tornado touched down, and people at Westmoore High School had time to shelter.

Outbreak Timeline

• 4:15 p.m. CDT: First severe thunderstorm warning, Comanche County.
• 4:47 p.m.: First tornado warning, Comanche, Caddo and Grady counties.
• About 4:51 p.m.: First tornado reported near Medicine Park.
• A little before 6:30 p.m.: The Bridge Creek-Moore tornado touches down near Amber.
• About 6:57 p.m.: The first tornado emergency is issued for the southern Oklahoma City metro area.
• Evening of May 3: Tornadoes also strike the Wichita, Kansas, area, killing five people.
• Morning of May 4: Nine more tornadoes form in Oklahoma, ending the outbreak.
• May 4: President Bill Clinton signs a major disaster declaration covering 11 Oklahoma counties.

Weather Service logs often list times in Central Standard Time or UTC rather than daylight time, so a time in a storm report can look an hour off. The guide to time zones in the United States and the explainer on daylight saving time help when converting those records.

Why Highway Overpasses Proved Deadly

Three highway overpasses were struck directly by tornadoes that evening, and each one became the site of a death. Two were along the F5’s path. One woman was blown out from under an Interstate 44 underpass in McClain County, and another was blown from under the Shields Boulevard overpass on Interstate 35 in Moore.

Many people believed an overpass offered shelter. Studies after May 3 found the opposite: the narrow space under a bridge can speed up the wind, much like water forced through a nozzle. A NOAA study concluded that a person sheltering there becomes “a stationary target for flying debris.”

Safe Rooms and the Lessons of May 3

Rebuilding focused on protection as well as repairs. A $12 million program over the next four years paid for storm shelters across the Oklahoma City metro area, and by May 2003, 6,016 safe rooms had been built. When an F4 tornado struck on May 9, 2003, along a similar path, no one was killed.

Moore was hit again on May 20, 2013, by an EF5 tornado that killed 24 people. The 1999 storm, by comparison, caused 36 direct deaths and 583 injuries. The 1999 calendar and the 2013 calendar show both dates, and the days between dates calculator counts the 14 years that separate them.