Nighttime tornadoes far more likely to turn deadly than those during the day

Tennessee has the highest percentage of nighttime tornadoes in the US, with 46% of its twisters happening in the dark

Tornadoes at any time of day can cause mass amounts of destruction and potentially kill those caught unprepared, but tornadoes in the dark are far more likely to turn deadly.

According to a study, tornadoes that occur at night – when many people are asleep – are more than twice as likely to become deadly than those during the day.

The study, led by Walker Ashley from Northern Illinois University and published in October 2008, examined data from the 48,165 tornadoes that were documented in the United States between 1950 and 2005 and found that only 27.3% of the twisters took place at night between sunset and sunrise.

However, that 27.3% of nighttime tornadoes were responsible for 39.3% of tornado fatalities and 42.1% of killer tornadoes during the 55-year period of study.

Put another way, about one in every 20 nocturnal tornadoes turned deadly, while only about one in every 50 daytime tornadoes were killers.


One reason for this is that tornadoes are typically unable to be seen in the dark unless the sky is lit up by frequent lightning. There are also fewer storm spotters willing to chase storms at night because of this reason, so that makes it even more difficult for meteorologists at the National Weather Service to confirm tornadoes on the ground in the dark, which might mean reduced lead time when issuing Tornado Warnings.

Additionally, tornadoes that occur overnight can catch many people off-guard because they may be sleeping and unaware of a dangerous twister potentially headed in their direction.

The highest percentage of nighttime tornadoes in the U.S. is found in the lower Arkansas, the lower and mid-Mississippi and the Tennessee River valleys, according to Ashley's study.

Tennessee leads the way, with 45.8% of its tornadoes happening in the dark. Arkansas sees 42.5% of its tornadoes between sunset and sunrise, while Kentucky has 41.5% of its twisters occurring at night.

Adding insult to injury, parts of the South can be at risk for tornadoes at any time of the year. Given the earlier sunsets in the fall and winter, any tornadoes during the colder months are more likely to occur at night since there's more darkness than daylight.

In fact, October, November and December are considered the second severe weather season for portions of the South. There's a notable peak in nighttime tornadoes in November, with the month averaging more than 400 twisters in the dark, according to data from NOAA's Storm Prediction Center.


Preparing for a twister ahead of time can help you stay safe in the event one sweeps through your area, whether it be night or day.

FOX Weather has compiled a list of steps you can take now to prepare for a future tornado.