I can't see a mention of a tornado in these pages so not sure what context it's referenced. Man of Steel had Clark's ship arrive at the start of a mammoth snowstorm that left the Kent farm cut off for several months, which allowed the Kents to say that Clark was their own. No one had any reason to doubt them (Where would you get a newborn kid when your farm is completely cut off?), and after multiple miscarriages, they were just happy that Martha had the child she (and Jon) had wanted.
I believe Millenium changed some of the "behind the scenes" stuff there, but I like to pretend that never happened.