UPDATED: Tornado outbreak- by the numbers and how rare is this?

HARRISONBURG, Va. (WHSV) - The December 10-11, 2021 tornado outbreak is an unfortunate one to add to the history books. I want to go over the data, what we know and what we don’t know and break this down.

Are December tornadoes rare?

Not at all. Tornadoes can happen at any time of the day, at any time of the year. Tornadoes have happened in every state and during every month. Typically we think of the spring when we think tornadoes and tornado outbreaks but the almost secondary season can be in the fall and winter for some parts of the country. There have been powerful tornadoes in December before.

Was this a well forecasted event?

The Storm Prediction Center did an excellent forecast with this storm system. While we can’t predict a tornado path of 200+ miles in advance, the ingredients were in place for a big severe weather event and concern grew each day getting closer to the event. All of the storm reports shown in the graphic below are within the risk area highlighted by SPC. The pink boxes are all the tornado warnings, the red triangles are the tornado reports. Hours before

How deadly was this outbreak?

This was an exceptionally deadly tornado outbreak. (UPDATED) As of Saturday, December 18th the death toll is believed to be 93 people. Of those, the death toll in Kentucky along is at 78. At least 55 people were injured. This is now the number one deadliest tornado outbreak for December.

It is also the deadliest tornado outbreak since May of 2011. (That is the outbreak that included the Joplin tornado which killed 158 people in Joplin alone).

This is not the deadliest tornado outbreak in U.S. History. That unfortunate statistic goes to the Tri-State tornado of 1925 which holds the record for the longest track tornado (219 mile path) and the deadliest tornado with 747 fatalities.

Here is a look at all of the tornado paths from the December 10-11 outbreak.

The count is at 61 tornadoes as of Sunday, December 19th. The number was updated after this graphic was made.

The December 15th Storm

Could this be the longest path for a tornado? (updated)

As of December 18th, the update is no but that still can change. One single supercell traveled more than 250 miles but according to the National Weather Service, it was two long track tornadoes on the ground. There is a gap in damage of about 14-15 miles in the far northwest corner of Tennessee. Per the potential for the longest track tornado, the NSW in Memphis states, “We are continuing to evaluate data from UAS, aircraft, and satellites regarding the storm`s evolution as it moved through Obion County. If the data from the supplemental sources reveals additional critical information, this statement will be updated.” Meaning, they are continuing to evaluate.

This image below from Jack Sillin is the one single cell. Not the path of a tornado. This was the contender for potentially the longest track “quad-state” tornado.

THE UPDATED SURVEY

The first part of that single storm cell started in Northeast Arkansas, moved into Missouri and northwestern Tennessee. That path length about 80 miles and that tornado was rated an EF-4 with winds of 170mph. At the tornado’s widest point, the width is estimated to be 1 miles and this tornado killed 5 people.

Right now there’s a gap in the damage that’s about 14/15 miles as stated above. The same storm produced a second tornado with a path of 165 miles. This is the tornado that went through Mayfield, Kentucky. Maximum winds are estimated to be 190 mph and the width of the tornado, more than a mile wide. There are at least 55 deaths attributed to this tornado.

In addition, there was another long track tornado through Tennessee into Kentucky. This path was 122 miles long. This one was rated an EF-3 with winds of 160mph.

LONGEST PATH TORNADOES

This is a look at the longest tornado paths in history per the Storm Prediction Center. These are listed in full path length but tornado surveys done before modern radar were difficult to complete. We can’t say for sure if some paths were completely continuous or if it was a family of tornados. That meaning that one supercell produced several tornadoes.

How can you help?

We know that the rebuilding process is going to take a long time and these areas affected need a lot of help.

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