JEFFREY BROWN: Finally tonight, chasing storms, science, and risk.
The National Weather Service said Friday's deadly tornado near Oklahoma City was stronger than initially reported. Meteorologists now classify it as an EF-5, the strongest ranking possible, with winds of 295 miles per hour. It was also the widest twister ever recorded, 2.6 miles. The storm and subsequent flooding killed 18 people.
Ray Suarez has more.
MAN: Tornado on the ground. Large tornado on the ground.
RAY SUAREZ: A storm chaser sounded the alert Friday evening as the enormous black funnel filled the dark sky just west of Oklahoma City.
Three of those killed were storm chasers themselves, Tim Samaras, 54, his son Paul, 24, and Carl Young, who was 45. They were working for the Discovery Channel. This was all that remained of their truck after it was caught in the open.
A colleague says escape was all but impossible.
BEN MCMILLAN, Storm Chaser: It was a really wild tornado. It was rapidly evolving. There was multiple tornadoes that turned into one larger tornado. And then the larger tornado went one way and then switched directions very quickly and went another way. It was just a really hard storm to track.
RAY SUAREZ: Indeed, this Weather Channel vehicle was picked up by the same storm and hurled 200 yards. Only one of its chase team of three was seriously hurt. It was all testimony to how inherently dangerous this profession is. But another colleague says Tim Samaras was known for his caution.
PAUL STOFER, Storm Chaser: He really knew what he was doing. He didn't chase for the notoriety or the television or selling video. He chased because he genuinely wanted to learn more about severe weather.
RAY SUAREZ: The Storm Prediction Center in Norman, Okla., says the men killed Friday appear to be the first scientific researchers to die in pursuit of tornadoes.