Notable May Severe Weather Outbreaks

 

Photo Credit - hail: Kristen Leitch

May is the height of severe weather season in the United States.  While some outbreaks have impacted the DC Metro Area, the strongest tornadoes tend to form in the Midwest and the South.  Some significant May outbreaks that have occurred in recent years are.

2019:  Three tornadoes touched down in central Maryland on May 30, producing two EF-0’s and an EF-1 in Frederick and Howard Counties.  Wind damage was more widespread across the DC Area, with a wind gust as high as 66 mph reported at Davison Army Airfield in Fairfax County, Virginia. 

Just a week earlier, even more severe weather impacted the D.C. Metro Area.  An EF-1 tornado was confirmed in Columbia, Maryland that caused some structural damage.  There were many severe wind gusts from the thunderstorms that developed.  Wind gusted as high as 66 mph at National Airport, 63 mph at Andrews AFB in Maryland, and 67 mph in Gaithersburg, Maryland.  Damage was reported that ranged from downed trees and power lines to minor structural damage of homes and businesses.

2016:  Large hail sometimes occurs in the Mid-Atlantic Region.  On May 2, Rockville, Maryland, had hail 2.5” – 2.75” in diameter, ranging in size from tennis ball to baseball.  Baseball-sized hail was also reported in Charles County, Maryland, while golf ball-size hail occurred in Huntingtown, MD.  There were other reports of hail in the D.C. Metro Area that were smaller.

2013:  The last EF-5 tornado in the United States occurred on May 20 in Moore, Oklahoma.  It had a long and destructive track as part of a larger, three-day severe weather outbreak.  The strongest tornadoes often develop from something called a “supercell thunderstorm,” which is a long lasting thunderstorm that has a rotating updraft. 

One of the supercell thunderstorms that developed during this outbreak spawned the Moore, OK tornado.  Although not at EF-5 intensity during its entire track, it reached peak intensity near the town of Moore.  According to NOAA, it caused two dozen fatalities and remains the third costliest tornado on record having caused $2 billion in damage (unadjusted for inflation). 

2011:  The town of Joplin, Missouri experienced a devastating EF-5 tornado on May 22.  According to NOAA, the Joplin EF-5 remains the costliest tornado on record having caused $2.8 billion in damages (unadjusted for inflation).  With a total of 181 fatalities, it was also the single deadliest U.S. tornado since 1947.  The spring of 2011 was an unusually active severe weather season in the United States with a total of six EF-5 tornadoes.  That was the highest annual total since 1974.