Story highlights
Moore hit by devastating twisters twice since 1999
The biggest tornadoes usually don't strike populated areas
Oklahoma has one of the highest climates
Estimated peak winds in Monday's deadly storm were between 200-210 mph
The governor of Oklahoma, Mary Fallin, says it is “hard to believe” another monster tornado could devastate the Oklahoma City suburb of Moore.
The odds of one striking the same place twice are extremely rare – rarer still if it’s near a populated area. But if that place is Moore, science may offer an explanation.
“Oklahoma has one of the highest climatological likelihoods for tornadoes of any place in the nation,” according to Bob Henson of the National Center for Atmospheric Research.
“So if two EF4/EF5 tornadoes are going to strike the same city within 15 years, Moore is as likely as any other place. Even so, this is an extremely rare occurrence,” Henson said.
On average, 10 tornadoes a year reach the most dangerous classification and almost never strike populated areas.
Monday’s deadly storm was the exception.
Oklahoma City area hammered by EF5 tornado in 1999
Moreover, it partly followed the path of an EF5 tornado that walloped metro Oklahoma City in 1999, killing three dozen people. That twister tracked a path that included Moore, a southern suburb of more than 50,000 people.
It was one of the costliest tornadoes in U.S. history.
Dallas-Fort Worth, Kansas City and St. Louis are also considered high risk for severe tornadoes, according to Harold Brooks of the National Oceanic and Atmospheric Administration’s Severe Storms Laboratory in Norman, Oklahoma.
Yet, none of those metro areas has been through what Moore has experienced.
Monday’s storm caused enormous property destruction and killed at least two dozen people.
“Yet it was a relatively ordinary violent tornado,” according to Brooks, an acknowledged expert on the climatology and probability of twisters.
Tornado prediction is improving
Such twisters are defined as those that have winds of at least 200 mph, are a half-a-mile or more wide, and produce the most fatalities.
When they touch down, they normally stay on the ground for 30 to 60 minutes.
The National Weather Service said Monday’s tornado was 1.3 miles wide as it tore through Moore.
The estimated peak winds ranged from 200 to 210 mph – which would make it an EF5, the most powerful category.
Judging by the vast destruction of homes and buildings, experts say it was on the ground for about 40 minutes.
The number of tornadoes overall seems to be more variable.
“In the last three years we have set records for the most tornadoes in 12 consecutive months and the least number of tornadoes in 12 consecutive months,” Brooks said.
He has no explanation for the inconsistency.
