Watchmen director Zack Snyder flew into a panic after learning about the devastating storms in Oklahoma last month (May13) because his daughter was in the town worst hit by the twister, visiting her boyfriend.

A number of deadly tornadoes touched down on the outskirts of Oklahoma City, and the town of Moore was ravaged by the natural disaster, which claimed the lives of 24 locals.

And Snyder admits he became a nervous wreck as he worried about his daughter's safety.

He tells USA Today, "She didn't tell me (she was going there). I was like, 'What are you doing?'"

And he had a difficult time watching news coverage of the residents running for cover: "I cannot express how upsetting it was... It's just insane."

Meanwhile, Snyder knows first-hand what's it like to encounter a twister in real life - because he and the cast and crew of his new Superman movie Man of Steel often encountered dangerous storms while filming in Illinois during the 2011 summer tornado season.

He adds, "I was freaked out as the tornado sirens were going off... I was like, 'This is crazy!'"

Ironically, there's a killer tornado scene in Snyder's new Superman film, and the director admits there was never any discussion about altering the twister footage following the Oklahoma storms.

The filmmaker states, "He's (Superman) changed by those events. If anything, we feel like our Superman has a connection - not to make light of it - to the kind of grief that happens during those kinds of natural disasters. Also, in a sad way, even Superman can't change that."