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A weather term few knew before resonates loudly after last summer's misery.
The Roanoke Times | File 2012
Andrew Morgan (center) and Josh Tiller, with Jacobs Tree Worx out of Vinton, clear trees off of a property on Holly Lane in Daleville on July 3, 2012. Morgan said it took days to eliminate the effects of the derecho.
The Roanoke Times | File 2012
A tree knocked over during the 2012 storms sits on a house on Race Street in New Castle.
The Roanoke Times | File 2012
Denise Garvey (left) and her mother Donna Alley play checkers at a cooling station set up in the New Castle High School cafeteria.
Friday, June 28, 2013
It was an ill wind that hasn’t stopped roaring through our minds, and a word we can’t get out of our heads.
“Derecho” rudely intruded into the everyday vocabulary of Southwest Virginians a year ago today, as a vicious windstorm stirred by a thunderstorm complex developed near Chicago in early afternoon, then sped southeastward, lengthening, intensifying and accelerating as it crossed through hundreds of miles of extremely hot, unstable air untapped by any other storms.
By 8 to 9:30 p.m., the derecho slammed into the New River and Roanoke valleys with 80 mph wind gusts that shook us from the lazy dusk of our hottest day since the 1980s and disrupted the lives of millions in the Ohio Valley, Appalachians and mid-Atlantic for several days.
Some 47 people were killed — 13 in the winds, 34 more in the stifling heat that followed as more than 4 million homes lost power, according to National Weather Service figures. At least four storm-related deaths occurred in the Roanoke and New River valleys.
It was a storm completely outside the experience of many Southwest Virginians.
Tree-bending – and tree-breaking — winds blew for half an hour or more in many locations, but little or no rain fell, as the storms emitting the powerful downdrafts largely dried up crossing the mountains.
A year later, the term “derecho” has not lost any resonance.
“On the plus side, it’s heightened awareness of non-rotating windstorms and taking severe storms more seriously,” said Phil Hysell, the warning coordination meteorologist at the National Weather Service in Blacksburg.“On the flip side, in some of the conversations I’ve had with people, they’ll say ‘It’s not a derecho, it’s not going to be that bad.’ ”
What is a derecho?
Just the mention of “derecho” now stirs interest, dread and fear.
The word was floated around liberally on social media before a June 13 severe weather setup that, in the end, did yield some corridors of significant wind damage in Southwest Virginia and, eventually, a somewhat controversial designation as a “low-end derecho” by the Storm Prediction Center in Norman, Okla.
“For the briefing slide leading up to June 13th, we had greater reach for that post than any other post we’ve had in the last year and a half on Facebook,” Hysell said.
“Certainly one of the first things when we talk about severe storms that people want to know is, ‘Oh, is it gonna be another derecho?’ ” said Steve Keighton, the science operations officer at the Blacksburg weather service office.
“But the term is often misapplied,” Keighton added. “Any windstorm that blows over a couple of trees, in some people’s minds, is a derecho.”
A derecho (pronounced “day-RAY-cho’) is defined in the National Oceanic and Atmospheric Administration’s online glossary as “a widespread and usually fast-moving windstorm associated with convection.”
Various technical papers have established severe wind damage — that produced by winds 58 mph or greater — stretching 240 miles in length as a baseline for derecho status. Some technical definitions require 75 mph winds at certain intervals. This is where debate develops about a particular storm system’s worthiness to be called a derecho.
There is no debate about June 29, 2012.
By 5 p.m., with the bowing squall line still yet to enter West Virginia, there was so little question that a derecho had already formed that the SPC began using the term in its forecast discussions.
Severe thunderstorm warnings were issued 30 or more minutes ahead of the high winds at most locations in Southwest Virginia But post-storm studies by the National Weather Service showed that most people reported not having warning on the storms.
“It was a Friday night in the middle of summer, so many people were out and about in their communities, away from their typical means of receiving warnings, such as television and radio,” said Jen Henderson, a doctoral candidate in Science and Technology Studies at Virginia Tech who was part of a National Oceanic and Atmospheric Administration derecho assessment team as a social scientist.
“It’s clear from the assessment that many people felt that they didn’t have enough warning. Many people said their first indication that a storm was coming came from the wind itself, as it blew branches and limbs across their yards,” Henderson said.
The Blacksburg office of the weather service has increased its presence on social media – both Facebook and Twitter – during the past year. The Wireless Emergency Alert also transmits some weather warnings on cellphones.
What isn’t likely is the use of the term “derecho” in a storm warning — unless forecasters are certain one is already occurring.
“If the SPC is already using that terminology upstream from us, we can use it too,” Keighton said.
Powerless in the heat
After Roanoke hit 104 degrees on June 29 — the hottest day since 1983 and hottest June day since 1936 — the temperature climbed back to 102 on June 30, with no cooling help from an almost rainless storm. From June 28 to July 8, all but one day hit at least 97 in Roanoke, with four topping 100, for the hottest 12-day period since 1930.
And many thousands had no air conditioning, some for more than a week after the derecho.
“A very surprising result was the fact that while there were over 51,000 customers without power in the city for multiple days during a heat wave, and at max, we only sheltered 150 persons and less than 10 pets,” said Mike Guzo, emergency management coordinator for the city of Roanoke.
Guzo said the city E-911 Center was overwhelmed with calls about power outages after the derecho and subsequent strong wind events. Such calls should instead be directed to Appalachian Power instead, he said.
The derecho made a broadside run across the heart of Appalachian’s service areas in West Virginia and Virginia. Appalachian spokesman Todd Burns said more than 500,000 customers — more than half of its customers — were without power shortly after the derecho.
Burns said Appalachian has widened some rights of way, the pathways where power lines are cut, to enable lines to withstand more wind, and also reduced the length of some circuits so fewer customers are affected by each problem.
“It was the biggest event, in terms of damage, in our company’s history,” Burns said. “Hopefully we don’t see anything like it for a long time to come.”
Dave Wert, the chief meteorologist at the weather service office in Blacksburg, was astounded by what he witnessed outside his home that day, as visitors barely dodged falling trees and limbs filled the air.
“I have never seen something sustained of that intensity in any of the tornado-centric areas I’ve worked,” said Wert, whose previous career stops included Norman, Okla., and both Omaha and North Platte in Nebraska, all in the heart of “Tornado Alley.”
It would seem from the deep impact that the 2012 derecho will join weather events like the 1993 blizzard and 1985 floods as those remembered for a generation or more in our region.
But officials are cognizant that the resonance of any weather event slowly decreases with time, and preparedness levels slowly
“The question is how long will the historical memory of the derecho stay alive in various communities,” Henderson said. “I suspect that this latest derecho has likely ensured its endurance in the community for at least a few more years.”
Staff writer Zach Crizer contributed to this report.
Weather JournalStorm track isn't very snowy for us