The National Weather Service has rated the tornado that hit the Moore area an EF5, the highest rating for a tornado.
Spokeswoman Keli Pirtle said Tuesday the agency upgraded the tornado from an EF-4 on the enhanced Fujita scale to an EF-5 based on what a damage assessment team saw on the ground. The weather service uses the word "incredible" to describe the power of EF-5 storms.
The weather service says the tornado's path was 17 miles long and 1.3 miles wide.
Pirtle says Monday's twister is the first EF-5 tornado of 2013.
At least 24 people were killed in the storm, nine of those victims were children. There is no exact number of how many people could still be missing.