First Alert Weather In-Depth: Moore, Oklahoma — the last time for an EF-5 tornado

We generally know the kind of intensity that a tornado can produce. Obviously, it is last thing we want to see in our neighborhood. Recently folks are remembering the 11-year anniversary of the Moore, Oklahoma tornado. This was the last time that we had a tornado of this magnitude in the United States.  It was really noteworthy for the incredible intensity, devastation and unfortunately the loss of life for this particular community. This twister leveled many areas, and pictures of the aftermath show the horror from Moore, Oklahoma. There is really nowhere to hide from something of this intensity. And in order to survive, you need to get out of the way or you have to go below ground. There were even some reports of asphalt being ripped up off of the ground.

The town of Moore is just outside of Oklahoma City and is considered a suburb, located about 10 miles south. The state of Oklahoma is no stranger to tornadoes as they are located the heart of “tornado alley.” The Enhanced Fujita Scale (EF Scale) goes from zero to five with zero being lowest intensity and five being the most intense. This particular tornado was rated as an EF-5 with winds estimated in excess of 210 miles per hour. Unfortunately, there were 24 deaths and it demolished 300 homes and structures.

How do we get a tornado of this kind of intensity? There are many ingredients, but initially we need a thunderstorm with strong winds at the lower level and the upper level with something called wind shear.  This shear is due to significant differences in speed and direction. This creates a column of rotating air that develops, and at some point that rotating air gets drawn up through the updraft of the thunderstorm. This is a mesocyclone that usually becomes a supercell thunderstorm.

Fortunately, over 75 years of record keeping, New York State has never reported an EF-5 tornado. Let us hope it stays that way!