From the ABC 7 Weather team

Why weren't this week's tornado deaths avoided?

April 29, 2011 - 03:30 PM
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How could this happen with all the advances in meteorology, the vast network of Doppler radars, warning systems and preparedness?

A parting shot of the tornado in Stafford County, Va.32 Photos
(Photo: Scot Gonzales /ABC7 viewers | Date: Apr. 27, 2011)

This week’s tragic tornado outbreak with the number of fatalities rising to over 300 will be one of the greatest losses of life from a tornado outbreak in U.S. history.

A chart of killer tornadoes. Click to view larger.

How could this happen with all the advances in meteorology, the vast network of Doppler radars, warning systems and preparedness? And is this outbreak something to do with climate change or global warming?

First, a look at the destruction of a highly populated area such as Tuscaloosa, Ala. The tornado that tore through Tuscaloosa was likely an EF-5, bringing winds of over 200 mph. Dr. Howard Bluestein, a long time tornado researcher, and others have measured winds speeds of 300 mph with research Doppler radars.

A category 1 hurricane has winds of 74 mph or higher, so imagine something with almost 20 times the power and force of a hurricane. Very few structures we build can remain standing in the face of an EF-5 tornado with winds of 200-300 mph. The great loss of life is caused in part by debris, wood, trees, even rocks being propelled to speeds of 100-200 mph in the heart of these monsters. Here is a video example.

Even with warnings of almost 30 minutes, as was given by the National Weather Service watching these terrible storms on NEXRAD Doppler radars, it was impossible for some people to survive a direct hit by an EF-5 tornado, even in a home with modern construction, unless they were in an underground storm cellar, a protected area of the basement.

There will be many stories to come of debris and personal belongings being carried sometimes hundreds of miles by such deadly storms. The many direct hits we have seen of cities such as Tuscaloosa, Birmingham,  and Memphis this month should do away with the myth that tornadoes don’t hit large cities.

Not only the ferocity of the this high-powered tornado, but the length and life of its path was the cause of such a terrible loss of life.

Scientists are learning more and more about what causes a tornado “tornadogenesis." Preparing a densely populated area for a once-in-500-years event is a challenge.

Now the climate change/global warming question. Andrew Freedman with Climate Central wrote Friday:

Climate change is already changing the environment in which severe thunderstorms and their associated tornadoes form, and it's bound to have some sort of influence on tornado frequency or strength. But as of now, no discernible trend has been detected in the observational data, and studies of how tornadoes will fare in a warmer world show somewhat conflicting results.”

I have done interviews with Andrew and he has a wonderful blog post about the subject.

This year being a La Nina year does seem to increase the probability of early-season and strong tornadoes, based on recent research, and the water temperature of the Gulf of Mexico is also a bit warming than average right now. Some areas in southern Alabama are already at 80 degrees. The source of the warm, humid air that is the fuel for the monster thunderstorms.

Some may ask: Why we can’t do something about these killer storms? The answer is, they are more powerful than anything we can create. The tornado, even an EF-5 monster, is but a tiny part of a massive storm that may be 20 miles in diameter, extend some 10 miles high to the top of the atmosphere, and be rotating. It generates tens of lightning bolts per second, millions of tons of hail, extreme turbulence, gulpes ten cubic miles of air every minute and releases power comparably to that of nuclear weapons. Imagine trying to stop or change this. And if somehow we could change the path of a tornado, do we know where it would go?

We have to continue learning more to give even more advance warning. Better communicate the extreme and life-threatening danger not only for tornadoes but for all dangerous weather events. And in the end, prepare and hope a tornado doesn’t come near our neighborhoods.

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