Word of the Day: “Derecho”

July 2, 2012

Why do I suspect that in 10 years, a lot more people will know how to pronounce “derecho”?


Derechos (long-lived violent windstorms) defined as having to travel at least 240 miles with wind speeds of at least 58 mph, easily made that mark yesterday creating a swath of wind damage of nearly 800 miles long and 500 miles wide with peak winds speeds between 80 and 100 mph.

The storm was birthed around the Chicagoland area Thursday morning with winds between 70 and 90 mph, but then really began to take shape in Indiana.

The destrcuctive windstorm traveled through as many as 9 states (Indiana, Ohio, Kentucky, Pennsylvania, West Virginia, Virginia, Maryland, North Carolina, and New Jersey).

The violent windstorm left at least three injured in Virginia, one injured both in Indiana and Ohio, and at least one dead in both Kentucky and Virginia. Approximately 3.5 million from Indiana to the East Coast lost power including about 1.5 million in Maryland and Virginia.

The derecho has been characterized as being worst than Hurricane Irene of 2011 in southern New Jersey. Statewide Emergency Declarations in have been ordered in West Virginia, and also for parts of New Jersey.


— “A derecho (pronounced similar to “deh-REY-cho” in English… ) is a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms. Although a derecho can produce destruction similar to that of tornadoes, the damage typically is directed in one direction along a relatively straight swath. As a result, the term ‘straight-line wind damage’ sometimes is used to describe derecho damage. By definition, if the wind damage swath extends more than 240 miles … and includes wind gusts of at least 58 mph … or greater along most of its length, then the event may be classified as a derecho. ”

— “The word ‘derecho’ was coined by Dr. Gustavus Hinrichs, a physics professor at the University of Iowa, in a paper published in the American Meteorological Journal in 1888.”

— “Derechos are associated with bands of showers or thunderstorms (collectively referred to as ‘convection’) that assume a curved or bowed shape. The bow-shaped storms are called bow echoes. … Derecho winds are the product of what meteorologists call ‘downbursts.’ A downburst is a concentrated area of strong wind produced by a convective downdraft. Downbursts have horizontal dimensions of about 4 to 6 miles (8 to 10 kilometers), and may last for several minutes.”

— “Derechos in the United States are most common in the late spring and summer (May through August), with more than 75% occurring between April and August. … [They] most commonly occur along two axes. One extends along the ‘Corn Belt’ from the upper Mississippi Valley southeast into the Ohio Valley, and the other from the southern Plains northeast into the mid Mississippi Valley.”

As for the term itself, according to a paper written by retired National Weather Service forecaster Robert Johns, the University of Iowa’s Hinrichs “decided to use the term derecho (Spanish for ‘direct or straight ahead’) to define these non-tornadic events since this term could be considered as an analog to the term tornado which is also of Spanish origin.”

Detroit Free Press:

When a hurricane is lumbering their way, state officials have time to get extra personnel in place so they can immediately start on cleanup. That wasn’t the case with this storm, known as a “derecho” — a straight-line windstorm that sweeps over a large area at high speed.

“Unlike a polite hurricane that gives you three days of warning, this storm gave us all the impact of a hurricane without any of the warning of a hurricane,” Maryland Gov. Martin O’Malley said.

6 Responses to “Word of the Day: “Derecho””

  1. neilrieck Says:

    Yep, I heard the word for the first time on a CBC weather report yesterday. The presenter (not an accredited meteorologist) said “derecho” was the Spanish word for straight. Now this guy gave a questionable explanation for “what was straight” so I turned to Wikipedia for more insight:


  2. […] Why do I suspect that in 10 years, a lot more people will know how to pronounce “derecho”?  Examiner.com: Derechos (long-lived violent windstorms) defined as having to travel at least …  […]

  3. otter17 Says:

    Like a bunch of storm system lines squashed together. Doesn’t look like it was fun. Pittsburgh received just a glancing blow.

  4. […] b) In doing this, people in India and Africa will demonstrate how to build an electricity supply that is not as vulnerable as the highly centralized and interdependent systems that  is currently causing so much difficulty in the mid-atlantic states, following last week’s super-Derecho event. […]

  5. “Why do I suspect that in 10 years, a lot more people will know how to pronounce “derecho”?”

    I just mentioned to a friend yesterday that this term and “haboob” are two words that we used in graduate school that were strictly “weather speak” at the time but are now becoming laymen terms–only because they are happening more often and more people are being affected by them.

    I’ve been hesitant to associate the increase of extreme weather/climate events directly with climate change (yet), but my gut says they’re linked and that we are going to continue to see an upward trend. My background is meteorology, not climatology, so I’m no expert in historical distribution, but it seems to me that we are seeing events that might not necessarily be any more intense than historical ones (living in the Dust Bowl area, I know it *can* be worse), but the ones we’re seeing are more widespread and perhaps even longer-lived.

    I hope I’m wrong, but I suspect we’re only yet seeing a glimpse of what’s to come.

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