Well, Blow Me Down! Inside A Derecho

A derecho doesn't happen as often as a tornado, but when it does, it can be every bit as destructive. Learn more!

In 2012, a massive straight-line storm system spanning more than 700 miles devastated large sections of the Midwest and Mid-Atlantic regions and added a new word to the weather vocabulary of many Americans—derecho.

What is a Derecho?

This type of storm system is relatively rare when compared to other types of destructive weather events, such as tornadoes and hurricanes.

Only a small area of the United States, centered on the Oklahoma, Missouri, Iowa states, sees more than one derecho event per year, on average. A surrounding region encompassing most of the Eastern U.S. sees a gradually lessening frequency of the storms, based on distance from this epicenter, with outlying areas such as Vermont and West Texas and the Southeastern Coast seeing no more than one derecho every four years.

A derecho is defined as “a widespread, long-lived, straight-line windstorm that is associated with a fast-moving band of severe thunderstorms.” The name “derecho” comes from the Spanish word for “straight,” (la derecha is “right” for those wondering) as opposed to other destructive wind events, such as tornadoes, that tend to be cyclonic in nature.

To be classified as a derecho, a storm must meet all of the following qualifications:

  1. There must be a concentrated area of wind gusts greater than 50 knots, or 60 miles per hour.
  2. The storm must have a major axis length of 248 miles or more.
  3. Wind must occur in a continuous and nonrandom pattern.
  4. There must be at least three reports, separated by 40 miles or more of wind gusts greater than 64 knots, or 74 mph.
  5. No more than three hours can elapse between successive wind damage events.

A Warm-Weather Phenomenon

Derechos are generally a warm-weather phenomenon, occurring mostly in summer, usually between May and August in North America, with peak activity during June and July.

Derechos are made even more dangerous by their relative silence. While most major thunderstorms can be heard approaching from several miles away, derechos can strike suddenly, with little to no warning. A derecho’s violent winds can uproot trees and damage structures in a very short period of time, leaving a wake of destruction before anyone even knows what happened.

Have you ever experienced a derecho? Share your stories below!

Farmers' Almanac - Itch
Jaime McLeod

Jaime McLeod is a longtime journalist who has written for a wide variety of newspapers, magazines, and websites, including MTV.com. She enjoys the outdoors, growing and eating organic food, and is interested in all aspects of natural wellness.

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missy

Don’t you love how these new radar systems determine just what happened after the fact ? Most of these storms now are called straight line winds doing the damage. So a straight line wind picks up a 140 year old tree uproots it totally, then takes a car and puts it on top of the tree and that is called straight wind damage. GO Back to the old system at least you knew what you were dealing with. But quit calling all this damage that is happening straigh line winds.

CDB

At the age of 14, I was with my mother and her sister who loved fishing the banks of local creeks and streams in northern Indiana. July 4th, 1969 we were heading back to our cars, some distance away, when suddenly, what seemed to me to be the sound of a massive bee swarm, came over us but had no apparent source. In a brief moment later there was a sharp drop in the temperature. The change was shockingly cold. The change felt stingingly cold, but the the sight of our bright sunny day, turned almost instantly dark by roiling, ominous clouds, chilled me with horror. In a suddenly whipping wind, my aunt and mom hurried us to the cars. We had dealt with tornadoes before, but in my short life and experience with them, this was nothing like I had experienced before. While running, I worried we wouldn’t make it in time and I clearly remember wondering if this was the end of the world; it was that frightening.

George

Got caught in this thing as we were rebuilding a chimney on a 2 story house on the north east side of Denver- older part of town.
We had just set up a makeshift roof platform that morning and were halfway through the rebuild process after having done the teardown earlier.
My partner was keeping an eye on this thing as it was heading toward us thinking we still had an hour before it would impact us.
As we were making good progress, I didnt want to get off the roof until we had to.
My partner said, damn- this thing will be here in less than 10 minutes! I opted to keep working until it started to rain.
I quickly made my way down when the rain started, thinking my partner was right behind me.
By the time I got down and made it around the side of the house to the covered front of the porch, the winds hit the trees in the yard and started to shake our platform so violently that he was afraid to climb down and could only hug the tall ladder for dear life.
He got a very brief lull in the winds and quickly clambered down.
This storm had 2 distinct parts to it as it abated for a moment before the winds resumed this time bringing some pea sized hail that only lasted a minute but but beat up gardens and tree leaves pretty badly.
The whole thing only lasted 10 minutes, never saw a severe storm move so fast- some of the winds were at least in the 70 mph range- felt like the florida hurricane winds I have experienced and was the only thing I could liken it to.
15 ft from where we were working, a 20 ft tall tree snapped in half and large tree branches were down sporadically everywhere.
The neighbors chimney didnt fair so well, but the one we were rebuilding was still standing.
George with Mile High Chimney Denver.

Drake

This was years ago back when I was in school. How long ago? Think 31 years ago, that’s how long and I remember it well. Joplin Missouri I was in school trying out for track since I was fast on my feet back then, not that fast anymore, haha. But we were outside at the football field running track and we were there for the weather said clear day all day. I am guessing that these storms brews and comes quickly and passes just as fast. But I remember seeing this straight line of extremely dark clouds that with the way they look, looks like rolling waves on the ocean. I pointed it out to my coach by saying, “Tsunami in the sky coming this way.” She turned to see it coming it for us and immediately ordered everyone to go inside the locker building close by. Before we could make it there, we were in a rough downpour with winds that blew everyone down as we tried to make it inside. It only lasted about 20 mins at the most but it was enough to rip up the tree next to the field and land it across the track, blow over the basketball goal by bending the pole over. And the trashcans, well I am not sure that they found them all but they were no longer on the field or by the bleachers. It was a scary time for us that day. At first, I thought it was a tornado since I had yet to see one but learned that it was not but a line of wind and rain. It was a few years later that I saw my first tornado and believe me, I would rather see a few more tornadoes before going through another Derecho.

Allison Falls

I was in Alderson wv 2012 @ Fireman’s Rodeo with 9 other Fire Dept. When sky’s turned black and all of sudden everyone’s radios went off and out of no where the wind came . 70 mph Turning things upside down. We grab everyone and went to school. It’s a horrific sight.
So please take heed to these storms
Be safe and God Bless

Susan Eckard

I was in the June 2012 Derecho in WV. It was devastating to many in this state. The sky got real dark and out of nowhere the wind was like hurricane force blowing down trees and powerlines. it was short lived with little rain, lightening or thunder. My son and his family were without power for 2 weeks because of the widespread damage.

Angela Degooyer

I have a video from last year in St. Catharines Ontario Canada that I believe was one , unfortunately I have no way to post it here . Let me know where and I’ll send you the video .

Shawn g

July 2014 was camping on Madeline Island, Lake Superior. It was our last night camping. I can’t remember the exact time but it was in the middle of the night. We were in our pop up camper. I woke to a rumbling noise coming out of the east and it was getting closer and louder. I thought it may be thunder but it was a constant rumble. The wind picked up severely and it started pouring, We had the inside flaps partially down inside the camper for ventilation when the rain started coming in. My wife woke up, closed her flap, and fell back asleep. The wind died down soon after that and the rain subsided, but another rumbling soon followed, the wind picked up and the rain came. Mind you it is pitch black in the camper and in the woods where we were under 30 foot pine and birch trees and I’m waiting for trees to come crashing down. The storm finally passed. The next morning it was calm and we packed up quickly, drove not more than a mile when we saw tree limbs down, power lines and also some full trees down, one had crashed through a garage. Waiting at the harbor the car Ferry docks and unloads numerous electric company vehicles with basket cranes and a couple Red Cross vehicles so we are thinking that there was major damage or injuries on the island. We came to find out later that the Red Cross was there for a blood drive, but there were down power lines for the electric company to fix. It was a spooky storm in the darkness of the night and I can understand when people say tornadoes sound like trains rolling through. I posted comments on Facebook when we got back and had one of my high school buddies respond with a national weather radar map showing the path and strength of the derecho, a term I had never heard of. It started in North Dakota and swept into wisconsin within hours. It was tracked for 600 miles in 12 hours- 50 miles per hour! I would hate to be in any of the storms that people were talking about wind speeds of 90-100 mph. I still have the radar track on my computer.

Mark Younger

Memphis TN had one that was named Hurrican Elvis -On July 22, 2003, a progressive derecho with straight-line winds in excess of 100 miles per hour (160 km/h) struck Crittenden, DeSoto, Fayette, and Shelby Counties, including the city of Memphis. The storm passed through the area between 6 and 7 am.

lidia

I am no Spanish expert, but i remember derecha means right, derecho means straight or “straight ahead”. I think it is confusing because English speakers will use “its right up ahead”, meaning keep on this track, not turn right up ahead.

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