by Shirley Love

Created on: April 27, 2009

As a native of northern Oklahoma, I have viewed and experienced numerous tornadoes in my lifetime. None of those experiences are forgotten, although after more than seven decades some are a bit dimmed in my memory. I will endeavor to explain the difference between the fact and the fiction of this deadly destructive force of nature based on scientific sources as well as some of my personal experiences.

1. Tornadoes and cyclones are the same. (Fiction) They are different in spite of the fact that they are often referred to by either name.

My first experience was at the tender age of six. We were traveling from Oklahoma to Kansas to visit my grandfather when a super storm formed behind us. My aunt and I were riding in the rumble seat of my uncle's car and as the storm began to overtake us, we were pelted with huge raindrops and hail. My uncle found a gas station with a covered drive and we took refuge there until the storm passed.

We could see a huge dark cloud to our east that covered the landscape from sky to ground, but we could not see a funnel. There was a deafening roar within that cloud, and my aunt remarked that it was probably a cyclone. After the sky cleared and the storm moved on, we could see the debris trail and the twisted trees that had been stripped of their bark.

It would be several years later before the term "rain wrapped" had a meaning for me, but I know now that described the storm we witnessed.

Although the term "cyclone" was used often in those days, we know for a fact that it is not the proper definition.

source: www.aoml.noaa.gov/hrd/tcfaq/L1.html
While both tropical cyclones and tornadoes are atmospheric vortices, they have little in common. Tornadoes have diameters on the scale of 100s of meters and are produced from a single convective storm (i.e. a thunderstorm or cumulonimbus). A tropical cyclone, however, has a diameter on the scale of 100s of *kilometers* and is comprised of several to dozens of convective storms. Additionally, while tornadoes require substantial vertical shear of the horizontal winds (i.e. change of wind speed and/or direction with height) to provide ideal conditions for tornado genesis, tropical cyclones require very low values (less than 10 m/s [20 kt, 23 mph]) of tropospheric vertical shear in order to form and grow. These vertical shear values are indicative of the horizontal temperature fields for each phenomenon: tornadoes are produced in regions of large temperature gradient, while tropical cyclones are generated

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