WYNNEWOOD, Okla. – Severe storms claimed lives, destroyed homes and injured livestock across southern Oklahoma on Monday evening.
Shortly after 4 p.m., a tornado developed near Elmore City and continued east toward Wynnewood, leaving behind a trail of destruction.

Crews with the National Weather Service surveyed the damage on Tuesday morning to learn more about the storm.
1117am – we can confirm at least EF3 damage with the tornado west of I-35 near Katie (SW of Wynnewood).
— NWS Norman (@NWSNorman) May 10, 2016
Officials say the tornado was at least an EF-3 when it hit structures near the town of Katie.
On Tuesday afternoon, the National Weather Service announced that the tornado that tore through Sulphur was also a high-end EF-3 and was one-mile wide at times.

Katie tornado (W of I-35) and Sulphur (E of I-35) both high end EF3. Sulphur tornado was one mile wide at times according to survey.
— NWS Norman (@NWSNorman) May 10, 2016
According to the Enhanced Fujita Scale, a tornado would register as an EF-3 when its wind gusts are between 136 and 165 miles per hour however the strength
of the tornado is based on damage. KFOR Meteorologist Emily Sutton explains below.

The National Weather Service says that the most intense damage they have found has been near the town of Katie, just west of I-35 and southwest of Wynnewood.
In all, seven tornadoes were confirmed from Monday evening.
The areas that were affected include Stillwater, Norman, Katie, Sulphur, Bromide, Atoka/Wapanucka and Bennington.