Tim Samaras, 55, a leading storm chaser and founder of the tornado research company Twistex, was killed in the Oklahoma City suburb of El Reno along with his son, Paul Samaras, 24, and Carl Young, 45, a Twistex meteorologist, according to a statement from Tim Samaras' brother, Jim Samaras.
Five tornadoes touched down in central Oklahoma and caused flash flooding just 11 days after a twister categorized as EF5, the most powerful ranking, tore up the Oklahoma City suburb of Moore and killed 24 people. Severe storms also swept into neighbouring Missouri, while Moore experienced only limited damage.
The Oklahoma Office of the Chief Medical Examiner increased the death toll to 10 after listing nine fatalities on Saturday.
As usual, so-called storm chasers closely tracked the storm to measure its power, gather research and take video to feed the television and Internet appetite for dramatic images.
"It is too early to say specifically how this tornado might change how we cover severe weather, but we certainly plan to review and discuss this incident," said David Blumenthal, a spokesman for The Weather Channel, for which Tim Samaras and Young had worked in the past.
Three employees of the channel suffered minor injuries when their sport-utility vehicle was thrown some 200 yards by the winds while tracking the El Reno storm on Friday.
In a field known for risk-takers seeking the most dramatic video images of tornadoes, Samaras was seen as a cautious professional whose driving passion was research rather than getting the "money shot," said friend and fellow storm chaser Tony Laubach.
"Tim Samaras was the best there was and he was the last person you would think this would happen to," said Laubach, a photojournalist who had been storm chasing with Samaras since 2007.
"It's going to bring everybody down to earth. A lot of chasing has been getting very, very careless, and Tim is not a careless person. He is as nimble and skilled as he could be," Laubach said.
In interviews, Samaras said he had been enthralled by tornadoes ever since childhood when he was forced to watch the movie "The Wizard of Oz", in which the central character is swept into another world by a tornado.
"That tornado was the best part of the entire movie," he told The Weather Channel in an interview in 2009. "From that day, I was hooked for the rest of my life."
While the public fascination with tornadoes has increased competition for images, trial lawyer Martin Garbus said it would be "impossible" to hold media companies liable for injuries storm chasers suffered while doing their job.
Like war correspondents, storm chasers assume personal risks when they enter danger zones, said Garbus, a partner at law firm Eaton & Van Winkle. This acknowledged job hazard protects media companies from negligence lawsuits, he said.
The negligence argument would be "you put me in the line of fire," Garbus said. But for storm chasers, "you assume the risk of where you go, you knew where you were going."
Samaras founded Twistex, based in Colorado, to collect temperature, humidity, pressure and wind-speed data with the goal of increasing lead times for tornado warnings. Some of Samaras' research was funded by the 18 grants he received over the years from the National Geographic Society.
The society routinely asks grant applicants to assess the dangers posed by their expeditions, and tells grantees to make safety their top priority, spokeswoman Barbara Moffet said
"Tim Samaras was among the most skilled professionals, and he was known for being meticulous about safety," Moffet said. "Unfortunately, research that involves nature's unpredictable forces can never be 100 percent safe."
Young was a meteorologist for Twistex and had joined Samaras on storm chases since 2003, according to Young's biography on the Discovery Channel's website.
Both men were featured in the now-canceled series "Storm Chasers" on the Discovery Channel, and had contributed to The Weather Channel in the past.
"Many of us were fortunate to have worked with them and have great admiration for their work," The Weather Channel said in a statement. "They went in the field focused on collecting data to enable meteorologists to further the science behind tornadoes which we know has and will help to save countless lives."
Paul Samaras was one of Tim's three children. He is survived by his wife Kathy Samaras and daughters Amy Samaras, 30, and Jennifer Samaras, 28.
