Weather officials say two tornadoes that killed two 76-year-old men in Oklahoma were more powerful than originally thought.
The National Weather Service on Wednesday upgraded two of Monday's tornadoes, including one to an EF4 near Katie that prompted the shut-down of Interstate 35 and one to an EF3 near Bromide. The tornadoes killed Chester Barnes of Wynnewood and Jackie Brooks of Milburn.
The tornado that killed Barnes is the first EF4 of the year to cause a fatality.
Weather service meteorologist Doug Speheger says his office upgraded the Katie tornado from EF3 and the Bromide tornado from EF1 after consulting further with survey teams.
An EF4 tornado bears wind speeds between 166 and 200 miles per hour while an EF3 wind speeds are from 136 to 165 mph.