Tim Marshall, Storm Tracker
Tim Marshall once traveled more than 1,000 miles to a little north of Grand Forks, N.D., chasing storms.
That trip was only one of the 175 tornadoes he has caught on tape in more than 30 years of storm chasing.
In 1981, Marshall tracked his first tornado through Warren, Okla., but saw his largest in 1999 in Moore, Okla.
When he's not chasing storms, Marshall works as an engineer and a meteorologist.