One year later, the term derecho resurfaces

In June 2012, one of the most destructive thunderstorm complexes in North American history swept through the D.C area. For many, the previously unknown word “derecho” – a term used to describe a powerful, tornado-like storm – became an immediate and distinct addition to local vocabularies.

“It’s interesting when a word like that catches so many people’s attention”, said NOAA’s Dr. Scott Rudlosky, an ESSIC/CICS Visiting Assistant Research Scientist and host of ESSIC extreme weather blog, “It’s Severe.”

The criteria for a derecho storm include damaging winds that exceed 58 miles per hour and a track length of at least 240 miles. This definition accurately describes the 18 hour period in June 2012, when a derecho system developed in the Midwest and traveled 600 miles in 10 hours, eventually reaching the Mid-Atlantic States. The storm resulted in widespread damage and millions of power outages.

Now nearly one year later, the term has resurfaced in discussion of potentially severe weather predicted for the D.C. area this week.

Although some meteorologists recognize the possibility for the development of a derecho storm this month, many remain unconvinced. The storms are very rare and highly difficult to predict, occurring on average of once every 3 to 4 years.

“People are certainly much more sensitive to the word derecho now. But it’s important to point out that last year the events all came together just right for that to occur, just at the right time. For that to happen again is very unlikely”, Rudlosky says.

As the anniversary of the 2012 storm approaches however, many local residents remain particularly cautious at the mention of severe thunderstorm development.

For additional info: See Rudlosky’s well read recap blog post on the 2012 derecho event.