John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Three major twisters have hit the city since 1999. Here's a look at how improbable that is.
Having an earth-shaking tornado obliterate your neighborhood must be an incredibly painful thing.
Now imagine what it feels like to have that powerful a twister level your home not once, but three times in under 15 years. That's the story of Moore, Oklahoma, a city of about 55,000 people that seems doomed to clockwork visits from immensely destructive thunderstorms.
“I can't think of any other city of that size in the country that's had three hits of this magnitude within that time span,” says Robert Henson, a meteorologist by training who writes for the National Center for Atmospheric Research. “That's the big part of what made this so additionally horrible. Any city hit by this [strong of a tornado] is awful, but the fact that they rebuilt twice before is just terrible.”
Residents of Moore are now struggling to pick up the very few pieces left behind by Monday's twister, which lurched out of a larger U.S. tornado outbreak to carve a 20-mile scar into the ground near Oklahoma City. The sucking vortex arrived in the early afternoon – an unusual time, given that many tornadoes form in later-day heat – and children were in school when it came roaring through. At least 24 people died in the storm, including many students.*
A massive tidal wave is what looked to have passed through Moore after the winds calmed, with residential neighborhoods reduced to flat checkerboards of house foundations. One news station reported that debris from Moore had fallen in Branson, Missouri, about 250 miles away. Take a tour with this helicopter cameraman and you'll begin to understand the magnitude of the calamity:
The National Weather Service has given the deadly spinner a preliminary rating of EF4 strength. “It was certainly a top-of-the-line tornado,” says Steven Corfidi, a meteorologist at NOAA's Storm Prediction Center. Henson says there's a chance it could be upgraded Tuesday to the fiercest category of EF5, after crews complete searches for damage indicators like lost roofs and collapsed masonry walls.
Tornadoes that spin to EF3 to EF5 strength are considered “violent” and carry powers that seem to bend the laws of physics, with winds that rip the bark off trees and hurl cars down the block like Scud missiles. Thankfully, they're rare. Out of the average of 1,253 twisters the U.S. gets each year, maybe 20 will rate as true EF3 to EF5 monsters.
That's why it's so weird that the relatively small city of Moore has been gobsmacked by a crushing series of super-intense ones. Here they are, in brief:
• May 8, 1999: The Great Plains Tornado Outbreak was the largest outbreak in Oklahoma's history, with reports of more than 70 twisters that killed 40 people in the state. One of these funnels entered Moore from the west and promptly flattened several clusters of homes. This tornado caused several deaths, including a woman it blew out from her hiding place under a highway overpass. It remains the strongest known tornado in the world, with winds that reached up to 318 m.p.h. (Rated EF5)
Here's a comparison of the paths of the 1999 and 2013 tornadoes:
(National Weather Service)
• May 3, 2003: Residents of Moore were unlucky enough to be included in a crazy storm outbreak that spawned about 400 twisters during one week in America. A weak funnel earlier in the day proved to be a decoy for a larger, swollen tornado that raged through the town's north, causing damage but no fatalities. (Rated EF3/EF4, depending on the source)
• May 20, 2013: Yesterday's tornado scored a particularly lethal blow due to a path that dragged it across the middle of the city. Locals were not helped by housing construction that The Atlantic's Alexis Madrigal reports did “not follow best practices for resisting a tornado's winds.” Oklahoma also tends to have “expansive soils” with a clay content that makes it difficult to build a basement. And basements are where you want to head when the radio chatter turns to imminent tornadoes.
Henson says he's struggling to find a good analogue for what's been happening in Moore since the late '90s. He can think of two examples of places with similar, uncanny tornado streaks. The first is Codell, a mere speck of a Kansas town that was struck by twisters in 1916, 1917 and 1918. The last one decimated hundreds of horses and cattle and wiped out much of the community.
The other place is Tinker Air Force Base in central Oklahoma, which absorbed a direct hit from a tornado on March 20, 1948. The vastly damaging storm – the costliest tornado in then-state history – set everyone at the base on high alert. So when the roiling skies started to look remarkably similar five days later, military meteorologists Robert Miller and Ernest Fawbush sent a warning to the brass that another twister looked nigh. A whopping twister did in fact descend upon the airfield that day, and history welcomed its first successful tornado forecast.
These are probably all stories of eerie coincidence. Tens of thousands of tornadoes have churned around the country in the past couple decades; you have to expect some places to have a lot more hits than others. It helps that Oklahoma is one of the most tornado-prone parts of the planet. If any place was destined to get nailed by years of deadly winds, it's not so strange that it's Moore.
“It's just the flat prairie of Oklahoma, with no particular features,” says Henson. “Nobody's established in science why one spot gets hit more than another.... This is simply the terrible luck of the draw.”
*Update: The death count from Monday's tornado was revised down Tuesday morning, from 51 to 24, likely due to "some double-counted deaths," according to the Huffington Post. The number could change again.
Top photo of destruction on Monday in Moore, Oklahoma, courtesy of Reuters/Gene Blevins