...Linn County, KS Experiences the First EF4 Tornado Ever Recorded...

On February 28th, 2007 a large and destructive tornado moved through Linn County, KS, taking a near 24 mile continuous path, where it caused damage to mainly rural areas. Although structural damage was isolated due to the rural track of the tornado, indications of a violent tornado were observed northwest of Blue Mound, KS where a single residence, garage, and several farm buildings were completely destroyed. Click here for the complete story of the event.


Experts from the National Weather Service office in Pleasant Hill, MO conducted a storm damage survey the following day, March 1st and have rated this tornado with a peak intensity of EF4 on the new Enhanced Fujita Scale. This rating corresponds to wind speeds estimated to be between 166 and 200 mph. In addition to local experts, numerous other nationally recognized damage survey experts have also viewed the data and have all supported a rating of EF4 for this tornado based on the evidence available. (see www.spc.noaa.gov/faq/tornado/ef-scale.html for more information on the Enhanced Fujita Scale) 


Photos below show the impressive size of this tornado, estimated between one quarter and one half mile in diameter. They were pulled from the video of an off duty National Weather Service employee who was out spotting this storm. Since the tornado occurred after dark, it was only visible when illuminated by intermittent lightning flashes. This is why it is so extremely important that folks take immediate action when a tornado warning is issued. If you wait to see or hear it, it may be too late!


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Photo Credits: Andy Fischer, Aviation Weather Center. Images may not be used without expressed written permission.

Radar imagery shown below shows the supercell and its rotational signature (center of both images) at about the same time as the above tornado images. These images clearly show a “hook” structure in the reflectivity field and a strong and tight rotational signature in the velocity field. These are a few of the features meteorologists look for when assessing a storm’s potential to produce tornadoes.


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This tornado is a historic event for a couple of reasons. First, it is the first time anywhere in the country that a tornado has been rated as high as EF4 since switching to the new Enhanced Fujita scale on February 1st 2007.  


Second, while tornadoes reaching EF4 intensity are rare events in their own right, there has never been a tornado of this magnitude occurring in Kansas this early in the year. Prior to this tornado, the earliest recorded occurrence of such a tornado in Kansas was on March 13, 1990. Most tornadoes of this magnitude in Kansas have occurred from late March through May. 


Please see www.spc.noaa.gov/faq/tornado/ef-scale.html for more information on the Enhanced Fujita Scale.

Please see http://www.nws.noaa.gov/om/brochures/tornado.shtml for more information on tornadoes, including important safety tips.

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