Associated Press

NORMAN, Oklahoma -- The National Weather Service has upgraded two of the tornadoes that hit central Oklahoma on Monday to EF-4 status.

The agency's Norman office said Friday a twister that traveled from Moore to Choctaw and another that started in Norman and traveled through Little Axe to Pink both had wind speeds of between 166 mph and 200 mph.

Tornadoes are rated from 0 to 5 on the Enhanced Fujita Scale based on the damage they cause. The weather service originally rated the two tornadoes as EF-3 storms.

Four other twisters in Oklahoma on Monday have been rated as EF-3. Fewer than 5 percent of tornadoes are rated as EF-3 or higher.

Rick Smith, a warning coordination meteorologist with the weather service, says the agency upgraded the status of the two storms after looking at photographic evidence and visiting damage sites that had previously been closed off.