One of the most intense outbreaks of tornadoes in OK history occurred on this date in 2011. The National Weather Service in Norman, OK has a very informative page from their website providing a detailed look back. There were several strong to violent tornadoes during the outbreak, the most intense being the El-Reno/Piedmont/Guthrie event which was rated EF-5. It was the second EF-5 to have occurred within 48 hours…the first being the Joplin, MO EF-5 on May 22, 2011.
Oklahoma is certainly no stranger to tornadoes in the strong to violent category and, depending on which statistics you go by, is either number one or two in F-5/EF-5 occurrence since 1950. Of course, storms don’t recognize political geographic boundaries, but the historical data is interesting nonetheless. Here’s a good retrospective of F-5/EF-5 tornadoes in OK going back to the beginning of the 20th century. Previous to that, record keeping was spotty at best. Detailed record keeping of tornado occurrence for the United States didn’t start until 1950…which is only a very short period of time from a climatological perspective. Determining what is or isn’t EF-5 damage is another incredibly complex challenge. This slide show (26 slide PDF file) will give you an idea of how difficult it can be to determine if the damage observed is worthy of an EF-5 rating.
Fortunately, for those of us who live in tornado prone regions, EF-4 & EF-5 events are rare and, depending on the number of tornadoes that have occurred, intensity of synoptic conditions, etc., they only make up from 0.5%-3% of the annual tornadoes in the US. But as our cities and populations grow, metropolitan areas and their suburbs are at an increasing risk of damage from all tornadoes, regardless of intensity.
Hope everyone is enjoying their spring…stay safe out there.