Are Extreme Tornadoes Becoming More Frequent?

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As I write this, people are still being pulled from the rubble in Oklahoma. Fatality reports were as high as 90, although some officials have claimed that the numbers have been exaggerated due to double counting.

Many of the fatalities are children. The kids were in their tornado positions (on your knees with your hands over your head) when a roof collapsed on top of them. Water lines broke and it is believed that the children drowned in the hallway where the roof collapsed.  Unbelievable.

Here is a photo courtesy of Christine Lightfritz:

OK_TORNADOBefore people start criticizing the forecasting of this outbreak, remember this:

There WAS advanced warning of severe weather and the strong possibility of tornadoes. In fact, last week, I remember mentioning the possibility for severe weather in the middle of the country late last week more than five days out.

The National Weather Service in Norman, Oklahoma, issued a tornado warning 16 minutes before it touched down; 30 minutes before it hit the population center of Moore, Oklahoma.  That might seem like a lot of time, but in a tornado situation, this is an eternity.  This doesn’t bring back the people lost but it does show that severe weather forecasting is getting better. Ultimately, this will save more lives in the long term.

Now the wind speeds…

Most wind speed measuring devices don’t survive the tornado. Only a few dozen tornadoes have has their winds directly measured. Maybe you’ve seen the “Doppler on Wheels” on storm chasing TV programs. The greatest wind speed EVER measured was done by “DOW” on May 3, 1999.

An NOAA's mobile doppler radar mounted on the back of a truck tracks a tornadic thunderstorm passing over ClearwaterAlthough the proliferation of these Doppler radars has increased as storm chasing becomes more frequent (partially driven by consumer demand–reality TV), the wind speed data from tornadoes is still determined by examining damage. The preliminary estimates rate this tornado as an EF4 according to the NWS office in Normal, Oklahoma. Some have speculated that this might be upgraded later.

5202013_EF4_trackHas EF5 tornado frequency increased? Data indicates that it has decreased overall since the 1970s.

tornadoEF3-5Only 58 tornadoes of EF5 strength have occurred since 1950. Most occurred in the 1950s, 60s and 70s. Here is the map with the tornadoes numbered in order of occurrence.

EF5tornado_mapOhio has had only 4 EF5 tornadoes since 1950! The last was in 1985