May’s Severe Weather

 

Photo Credit: NOAA

May is the height of severe weather season in the United States.  While some outbreaks have impacted the DC Metro Area, the strongest tornadoes form most often 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 Mid-Atlantic Region, 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 DC Metro Area.  An EF-1 tornado was confirmed in Columbia, Maryland that caused structural damage.  There were many severe wind gusts from the thunderstorms that developed.  Thunderstorm wind gusts were 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.

Tornado intensity is ranked on the Enhanced Fujita Scale with a minimal tornado being an EF-0 with winds of 65 mph – 85 mph.  The strongest and rarest tornadoes are ranked as an EF-5 with winds over 200 mph.

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 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.

2008: Several tornadoes developed in north central Virginia on May 8.  A weak tornado also developed in Camp Springs, Maryland.  The strongest tornado in the DC Metro Area during this outbreak was an EF-2 in Stafford County, Virginia with peak winds of 120 mph.  Many severe wind and hail events were also observed in Maryland and Virginia.