National Geographic explorer and storm researcher Tim Samaras set out to document tornadoes and lightning on a trip through Oklahoma. But a destructive hailstorm with some hailstones nearly softball-size was a surprise highlight of this day in the field. Joining Samaras on this day were photographer Carl Young and National Geographic photographer Carsten Peter.

EDITOR'S NOTE: Along with his son, Paul, and storm chaser Carl Young—his longtime collaborators—National Geographic explorer and storm chaser Tim Samaras died in a tornado in El Reno, Oklahoma, on May 31, 2013. He devoted his life to unlocking the mysteries of extreme weather.



Samaras June 2012NARRATION: Severe-storms researcher Tim Samaras went into the field this spring to document lightning and tornadoes for National Geographic.NARRATION: But sometimes, the unexpected happens, and with cameras rolling on this day near Watonga, and Kingfisher, Oklahoma, Tim and his team found themselves in the midst of a destructive hailstorm.SOT: Aw! There goes the windshield!NARRATION: But, this wasn't the worst of it.TIM SAMARAS: "Very strong inflow."NARRATION: A strong updraft is one of the main ingredients of a hailstorm.SOT: "Did you see that?TIM SAMARAS: "There they are. I got them. That was a huge hailstone. This is the real thing."SOT: "That will kill somebody!"CARTSEN PETER: "That's amazing."TIM SARAMAS: "I'm not so sure.... There's another one falling. I don't know, man. It's probably not safe to be out here."CARL YOUNG: "Oh! It's coming! It's starting to come in now. Let's get out of here!"CARL YOUNG: "My window's already broken, but I don't want the side windows to break."SOT: "Here's another one. Whoa!"CARL YOUNG: "Wow! Pretty big. Tim's got some. Wow -look at that monster! This needs to be measured."TIM SARAMAS: "That's four inches. There's another one."TIM SARAMAS: " Yeah, let's get out of here. [Laughs] You guys, we're going to get killed!"CARL YOUNG: "Look at this thing!"TIM SARAMAS: "Guys, come on!"CARL YOUNG: "Here we go. Look at this!"TIM SARAMAS: "I know! We better go! We're gonna die!"NARRATION: Baseball and softball sized hailstones falling by the thousands.TIM SARAMAS: "That is beautiful! Look at that!" NARRATION: Tim measured the biggest they collected at 4 inches... nearly the size of a softball. Any hail larger than one inch in diameter triggers a severe storm warning by the National Weather service, damaging to crops, people and animals and car windshields.SOT: Oh!NARRATION: Tim Samaras and his team will head back into the field in search of tornadoes, lightning... and maybe even another big hailstorm.