DERECHO: One Decade Later
WDBJ7 meteorologists look back at the deadly 2012 wind storm
ROANOKE, Va. (WDBJ) - It has been exactly one decade since the natural disaster most simply call “The Derecho” plowed through the region on a record hot summer day. 60 to 90 mph winds left whole counties powerless and nearly everyone wondering what the heck just happened?
WHAT IS A DERECHO?
The weather term, derecho, has actually been around since the late 1800s, but when you get hit by one of these wind storms, the unique name becomes unforgettable.
The damage looks like a tornado went through. But instead of spiraling winds like a twister, the winds of a derecho move in a straight line. That’s where the storm gets its name. In Spanish, the word derecho literally means “straight ahead.” Simply put, a derecho is a widespread, long-lived wind storm that’s normally associated with a band of showers or thunderstorms.
Thousands of storms with damaging wind form each year in the U.S., but very few of them actually become derechos. In fact, forecasters often don’t know whether it’s officially a derecho until after the storm damage is surveyed. That’s because there’s strict criteria for a wind storm to get that name.
- There must be reports of 58 plus mile per hour wind gusts and damage occurring over a path of at least 240 miles.
- Wind reports must show a pattern of chronological progression
- There can be no more that 3 hours that pass between wind damage and gust reports.
Our 2012 event checked all the boxes.
Believe it or not, the weather event of the decade started as a single storm near Chicago. What unfolded during the hours that followed was an unprecedented chain of events.
During the late afternoon, the single storm over the Midwest turned into a major complex fueled by the record-setting 100+ degree heat across Mid-Atlantic. Roanoke and Danville hit 104º, and Lynchburg hit 103º that afternoon. Not hardly a cloud in the sky locally that day, we went about our afternoon. At the same time, the wind storm was moving at interstate speed bringing 70 to 90 mph gusts into the Ohio Valley.
The first warnings from the National Weather Service were issued at 7:49 PM for areas along the Virginia/West Virginia border, as 80 mph winds were expected and trees and structural damage were reported.
Just an hour later, around 9 p.m. as the sun was setting in southwest Virginia, the wind for us was just beginning. The storms that typically weaken as they move west to east across the mountains held together, unleashing an incredible amount of wind.
Below are peak gusts and estimated time from the National Weather Service, Blacksburg.
|LOCATION||WIND GUST||ESTIMATED TIME|
|Roanoke||81 MPH||9:10 PM|
|Blacksburg||52 MPH||9:15 PM|
|Forest||56 MPH||9:30 PM|
|Lynchburg||55 MPH||9:54 PM|
|Goode||66 MPH||10:00 PM|
|Martinsville||56 MPH||10:00 PM|
For comparison, these types of wind gusts are much like an EF-1 tornado, but with much larger coverage.
Around midnight the wind storm finally dissolved out over the Atlantic Ocean. In all, the derecho left a historic mark on the region.
- Traveled about 700 miles in around less than 12 hours
- 13+ fatalities, mostly from falling trees
- 34 additional deaths due to the heat wave that followed
The knockout storm wasn’t without injuries and even deaths. The derecho resulted in 13 fatalities nationally, at least 3 of them locally. A husband and wife died during the storm when a downed power line sparked a fire at the couple’s home. In Franklin county, Boones Mill firefighter John Echternach was killed as he was responding to an emergency call.
The heat wave that continued after the Derecho caused even more frustration for those trying to cool off with no air conditioning. It had fatal consequences. An additional 34 deaths were reported due to heat-related illnesses.
The Derecho had widespread effects from the Ohio Valley and mid-Atlantic region. Over 4.2 million people lost power from the damaging winds. The top three states seeing the highest volume of power outages within AEP were West Virginia, Maryland, and Virginia.
In 2012, Kevin Smith was working as a line mechanic in the Lynchburg service area with Appalachian Power. He was on-call that evening and remembers being called to repair a bad transformer for one customer in the region. AEP began hearing reports of damage in neighboring states, and then the reports started getting closer.
“Our dispatch actually called us and asked us to hold up because of the strong winds. Everything then just hit the fan,” explains Smith.
He recalls the sky getting dark and the wind intensifying. At the same time, they started seeing power flashes from power lines hitting each other. He and his coworkers took shelter and knew this was a bigger event than just your average thunderstorm.
- 573-thousand customers without power in AEP territory
- 244-thousand customers in Virginia
- 2,000+ distribution poles replaced
- Biggest restoration effort in the company’s history
WHAT MADE IT DIFFICULT TO PREDICT?
Models the day before the 2012 event gave little to no indication that there would be a storm complex. The day of the storm, no severe weather was expected by forecasters in Virginia. By the end of the day, it would become one of the most memorable weather days in Virginia history.
To forecast a derecho, it is important to understand how one forms. There are two types of derechos: one being a serial derecho the other a progressive derecho. The 2012 derecho was progressive derecho, making the more difficult of the two to forecast.
“The serial derechos that form along a well-defined boundary that we can track on satellite and radar. Those are easier to predict,” explains Phil Hysell, Warning Coordination Meteorologist at the National Weather Service in Blacksburg. “What we had in 2012 was a progressive derecho, when once it develops, it moves away from a frontal system and the question is: where is it going to move?”
While thunderstorms are well forecast and understood, derechos are more complex and present a couple of large challenges.
The first big challenge is the imprecise nature of the observational network needed to produce an accurate picture of the atmosphere.
The NWS is limited to a finite number of weather balloons launched each day creating a gap in data. More frequent sampling is needed in the hours leading up to the event.
The other challenge is that we have an incomplete understanding of the processes that lead to repetitive, organized lines of storms. While often occurring on the fringes of major heat waves, two nearly identical meteorological settings might yield vastly different outcomes. In past cases, derechos have rarely crossed the Appalachian Mountains intact.
“These can cross those mountains if you have that amount of instability and energy in place. That was one of the key findings that came out of the after-action report from that event,” explains Hysell.
According to the Storm Prediction Center, significant advances in forecasting derechos will require further research along with a larger and more powerful weather sensing network.
Until then, it is a matter of bold forecasts and aggressive monitoring.
ADVANCEMENTS IN ALERTING SINCE 2012
Getting the word out to everyone that an epic wind storm was coming was nearly an impossible task. It was a Friday night, few were near a TV and our wall-to-wall coverage.
This was even the Facebook post giving several hours warning of the approaching storm. That just wasn’t enough.
What few know is that this single event sparked extensive research which helped reshape the way you receive weather alerts on your mobile device.
It’s common for our area to see thunderstorms. And when those get strong enough, a Severe Thunderstorm Warning is issued by the National Weather Service. However, research conducted after the Derecho showed the typical Severe Thunderstorm wording just wasn’t enough to get people prepared for what was about to happen.
Jen Henderson is an Assistant Professor of Human Geography at Texas Tech University. She was in the process of getting her Master’s Degree at Virginia Tech when the storm blew through. Henderson played an integral role in the post-storm discussion on better communicating the derecho risk.
“We learned they may not take the kind of sheltering that maybe the experts are expecting because when there’s a derecho coming through often the best protective action is what you would take for something like a tornado, but a severe thunderstorm warning doesn’t often convey that same kind of information,” explains Henderson.
Since the Derecho, the expected wind speed and possible hail size is now added to all Severe Thunderstorm Warnings that are issued.
“In 2020, we even refined that more to be able to put damage tags at the bottom of the severe thunderstorm warnings, explains Hysell.”
A Considerable Damage Tag means a storm may have 70 mph winds
When 80 mph winds are expected, a Destructive Damage tag is issued, which will automatically play an ear-piercing alert on mobile devices if you are in the warned area.
“We now have the capability of triggering the wireless emergency alerts on people’s cell phones that we didn’t have in 2012,” says Hysell. “I have no doubt that this would be messaged more broadly and people would get the information with more detail in that warning than they did in 2012.”
While social media, and generic weather sites may be fine for day-to-day weather, they can’t replace the specific information WDBJ7 meteorologists can deliver through Facebook Live, our 24/7 Weather Stream, and even through custom videos and alerts that can be geo-located and sent to the area of concern on the WDBJ7 Weather App. None of these existed in 2012 when the Derecho blew through.
Henderson worries, even with all the ways to get alerts, technology alone still may not be able to keep everyone safe.
“We also don’t think about all the other kinds of people who don’t have access to technology as often. People who are homeless, people who are older who might not find a need for a cell phone might rely on television and radio but not be watching on a Friday night when there is a storm going through.”
DAMAGE STILL VISIBLE TODAY
As you might imagine, trees were impacted most during this epic wind storm. It is estimated hundreds of thousands of them were either damaged or destroyed that day. Some of the damage is still visible one decade later, if you know where to look.
Dennis McCarthy, Senior Forester with Virginia Department of Forestry, took chief meteorologist Brent Watts on field trip into the woods to look for signs of the derecho.
“An opening in the canopy is what you would look for,” says McCarthy. The green vegetation, lush and dense is what you’d look for on the ground, and an open canopy above you where the light is now shining through.”
The sunlight beaming through the opening left by fallen trees has allowed vegetation to jumpstart. New seedlings begin growing in the same spots that were damaged.
An opening in the canopy is what you look for. When everything is green and lush, and look above and there’s an opening in the canopy.
“Young forests are a great way to identify those areas that may have been damaged. Forests are very resilient,” explains McCarthy.
An event most would consider a natural disaster, Denny has a different perspective.
“It’s more of a disturbance. Where we have thousands of acres of contiguous forest land, an event like this [Derecho] offers new growth and diversity in the species and plants. That also benefits wildlife,” adds McCarthy.
The logging industry also benefited from the 2012 event which turned downed trees into cash for those willing to put into some hard work. The clearing also helped mitigate forest fires by reducing the extra available fuel on the ground.
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