NOAA's National Centers for Environmental Information
Visit:NCEI U.S. Tornadoes
According to data from NOAA's Storm Prediction Center, during December, there were 46 confirmed tornado reports. This was nearly double the 1991-2010 average of 24 tornadoes for the month of December. Only five days during December recorded any tornadoes. The vast majority of the December tornadoes (39 of 46) occurred on December 9.
On December 9 there was an outbreak of 39 tornadoes across central Tennessee, southern Kentucky, central Mississippi, southeastern Alabama and the western Florida Panhandle. The damage produced from these tornadoes were rated as: two EF-0, five EF-1, four EF-2, one EF-3 and numerous as EF-U (unrated). One of the EF-2 tornadoes impacted Madison, Tennessee destroying numerous homes, businesses, vehicles and other infrastructure. This tornado also injured 22 and resulted in three fatalities. Another impactful tornado was an EF-3 that hit Clarksville, Tennessee, damaging or destroying numerous homes, outbuildings, vehicles and businesses. This tornado injured 62 and resulted in four fatalities. In total, the tornadoes of December 9th caused more than 90 injuries and seven fatalities.
Did You Know?
Tornado Count
Final monthly tornado counts are typically less than the preliminary count. This can be due to some phenomena being inaccurately reported as tornadic activity or a single tornado being reported multiple times. Tornado accounts are reported to the local National Weather Service forecast offices who are responsible for going into the field and verifying each tornado reported. This process often takes several months to complete. Once all reports have been investigated, the final count is published by the Storm Prediction Center (SPC).
The Tornado Monthly Climate Reports are written using the preliminary numbers because the final data is not available at the time of production. Historically, for every 100 preliminary tornado reports, at least 65 tornadoes are confirmed. An error bar is depicted on the tornado count graphic representing this uncertainty in the preliminary tornado count.
The following U.S. studies performed by SPC meteorologists offer deeper context and discussion regarding the frequency and distribution of tornado intensity climatologies:
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Edwards, R., H. E. Brooks, and H. Cohn, 2021: Changes in tornado climatology accompanying the Enhanced
Fujita scale. J. Appl. Meteor. Climatol., 60, 1465-1482
DOI: 10.1175/JAMC-D-21-0058.1. - Mccarthy, Daniel & Schaefer, Joseph. (2004). Tornado trends over the past thirty years. paper presented at 14th Conference on Applied Meteorology.