April Severe Weather Outbreaks

Severe Weather Reports from April 27, 2011  (NOAA)

The United States sees more severe weather and tornadoes in a given year than anywhere else in the world.  That’s attributed to the unique geography of the United States.  Severe weather consists of a thunderstorm that contains any one of the following: hail of at least 1” in diameter, wind gusts of 58 mph/+, or a tornado.  Large hail often precedes a tornado in the strongest, rotating thunderstorms known as “supercell” thunderstorms.  Some of the largest severe weather outbreaks on record have occurred in April.

2018:  From April 13 – 15, approximately 840 instances of severe weather were observed, including 95 tornadoes.  During this three-day period, severe weather was reported over a wide geographic area from South Dakota to Florida.  Four tornadoes were observed in southern Virginia on April 15.

2011: One of the largest severe weather outbreaks on record occurred from April 25 – 28.  NOAA’s Storm Prediction Center counted a four-day total of more than 2,300 severe weather reports, nationally.  Of that total, nearly 500 of those events were confirmed tornadoes.  The most active severe weather day of this four-day stretch was April 27, when nearly 300 tornadoes touched down and caused more than 200 fatalities.  A total of four EF-5 tornadoes were observed on April 27, 2011; and that remains the highest daily total since the “Super Outbreak” of April 3-4, 1974.  The DC Metro Area also saw some severe weather, including tornadoes, on April 27-28, 2011. 

2009:  On April 10, a total of more than 450 cases of severe weather were reported across the eastern United States, including more than 60 tornadoes.  Fortunately, no fatalities were reported and none of the severe weather occurred in the DC Metro Area.

According to NOAA, the state of Oklahoma had the fourth highest annual average for number of tornadoes (62) for the period from 1991 – 2010.  Some of the strongest and most destructive tornadoes on record have occurred in Oklahoma, including the 2013 Moore, Oklahoma tornado as well as the 1999 Oklahoma City tornado.  They ranked as EF-5 and F5 tornadoes, respectively, on the Fujita Scale.  (The Fujita Scale was updated in 2007 to become the “enhanced” Fujita Scale).  

Despite Oklahoma’s favorable geography for tornadoes, this year has gotten off to an unusually quiet start with no reported tornadoes yet.  NOAA records indicate this is the longest period of time that Oklahoma has gone to start the year without a tornado.