May is severe weather season

 

May 30, 2019 severe weather reports (Source: NOAA)

May is one of the most active severe weather months of the year in the United States. “Severe weather” is defined as a thunderstorm that produces any of the following: A) wind gusts of at least 58 mph; B) hail 1” in diameter or greater; or C) a tornado. 

The most dangerous thunderstorms (supercells) can have more than one type of severe weather as large hail often precedes tornadoes. Locally, the DMV has had a number of memorable May severe weather events.   

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 71 mph in Frederick County, Maryland, and a 66 mph gust that was reported at Davison Army Airfield in Fairfax County, Virginia. 

Just a week earlier, even more severe weather impacted the DMV. 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 68 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 DMV that were smaller, but still met severe criteria.

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. Although not as EF-5 intensity during its entire track, it reached peak intensity near the town of Moore.

According to NOAA, it caused more than two dozen fatalities and remains the third costliest tornado on record having caused $2 billion in damages (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 158 fatalities, it was also the single deadliest U.S. tornado since 1947. This was one of six EF-5 tornadoes that occurred in the United States in 2011, the highest such total since 1974 (7).