The calendar says October, which isn’t exactly known for being a month trademarked by tornadoes across the country… but something very interesting occurred this month when it comes to severe weather in this country that I wanted to highlight for you all.
The National Weather Service office in Grand Forks, North Dakota made some history this month when it upgraded a tornado there back in June to the EF5 level – the most intense and destructive category on the Enhanced Fujita scale that is used by the NWS to determine tornado intensity.
I talked with the Meteorologist in Charge at that office – Mindy Beerends – about the Enderlin tornado, which was initially rated as a high-end EF3.
“However, we were looking at some of the damage with that – primarily around the train derailment site. So, this particular tornado hit a train and derailed 33 train cars, including fully-loaded grain hopper cars. [It] not only just tipped them, but also lofted some further away from the track – anywhere from 600 to 1,000 feet,” she says. “While we saw damage to farmsteads and things while we were out there, it was this intense damage at the train site that really intrigued us – it’s not one of what we call our typical damage indicators that we use on the EF or Enhanced Fujita scale to rate tornadoes. So, it took a little bit longer to continue to look into how to determine a wind speed estimate that would cause this type of damage to these train cars.”
The Enhanced Fujita scale used by meteorologists at the National Weather Service to determine tornado strength was first adopted in 2007. It’s a revision of the original Fujita scale to include information on how most buildings and structures are constructed – an effort to more closely align how wind speeds from tornadoes translate to storm damage.
That process goes like this – the National Weather Service issues a Tornado Warning, and if damage is reported, the local NWS office will send out a survey crew. That crew will look at storm damage to see if it meets thresholds outlined in the EF scale – the more destruction you have, the higher the wind speed the tornado likely had.
It’s an interesting process because it’s done after a tornado rolls through.
Back to the Enderlin tornado itself… The new designation for its damage makes it the first EF5-rated tornado in the United States for over a decade (and there’s only been 10 to reach that mark since the Enhanced Fujita scale was adopted in 2007). The last EF5 tornado occurred in 2013 in Moore, Oklahoma – just outside Oklahoma City (and a personal aside about this tornado: I was out with the Hokie Storm Chasers for a field study experience required for my major in college at the time. I distinctly remember discussing the day of with my fellow classmates that the ingredients were all there for a particularly destructive severe weather outbreak... We decided to stay away from the Moore area because of safety concerns, and it was harrowing to see the media coverage of what transpired in the days after the tornado touched down).
I asked Beerends why it’s been so long since we’ve seen an EF5 tornado in the U.S…
“We’ve certainly had some strong tornadoes over the last decade and a lot of them have done considerable, devastating damage. But a lot of it has been that we have seen the observed damage analyzed by those offices – there were no known damage indicators at those times to support the EF5 damage in those tornadoes,” she explains.
This has always been fascinating to me because theoretically you could have a very strong tornado – one that matched the EF5 criteria of having wind speeds greater than 200 miles per hour – that wouldn’t be rated as one because it touched down in an unpopulated area and didn’t do significant damage.
“If it doesn’t hit something in its path at that intensity, then we don’t have a way to know how strong it could have been at the time,” Beerends says.
But this is just the nature of analyzing tornadoes! In the grand scheme of weather systems, tornadoes are pretty small scale when you think about it – they touch down across streets and neighborhoods as opposed to the more regional and statewide impacts you can see with something like a hurricane. Beerends says it’s just a challenge getting observational equipment like low-level radars (the plot of a recent summer blockbuster) in front of a tornado before it touches down, so we must rely on this post-tornado scale to determine intensity.
Closer to home, Virginia has never had an EF5 tornado – but there have been a couple EF4 ones and several high-end EF3s according to Jeff Orrock – the Meteorologist in Charge at the Wakefield, Virginia National Weather Service office.
I asked him if Virginia could ever see an EF5. While you never want to say never when it comes to the weather, but the threshold for that strongest intensity level is difficult to meet.
“It’s hard for us to even get to 4s; 3s are so much more common,” he says. “There’s just been so few EF5s. I’ve been on service assessments and surveys across the entire country, and I’ve never really surveyed too many EF5s. 5s are very, very hard to come by. You can go a very long time and not see an EF5 in various parts of the country.”
Orrock stresses, though, that even EF2 and EF3 tornadoes can cause extreme destruction, so it’s vital to heed Tornado Warnings and seek proper shelter anytime one is issued. That’s especially true for folks who live in mobile homes, which can be destroyed by just EF2 tornadoes.
Virginia officials urge caution as fall fire season gets underway
Virginia's fall fire season has begun.
The state’s Department of Forestry says firefighters have been stationed across the Commonwealth to assist local and federal partners throughout the season – which runs until November 30th.
Department officials are urging all Virginians to use extreme caution with campfires and debris burning – as careless, outdoor burning is the number one cause of wildfires in the state. That includes avoiding outside burns on dry, windy days and keeping a rake or shovel and a water source nearby in case you do decide to burn something.
People in Southwest Virginia should be especially cautious due to downed trees and debris from last year’s Hurricane Helene – which provides extra fuel for any potential blazes.
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