A Perfect Storm: Warm Winter Helped Spawn Deadly Tornado
March 07, 2012
By David A. Mann, The Evening News and the Tribune
"It was almost the perfect tornado maker," said Mike Callahan, hydrologist at the weather service.
The jet stream was positioned perfectly. Winds were strong and moving in a different direction in the upper levels of the atmosphere than they were on the surface, creating directional shear. And a warm front had passed through the area earlier in the day.
"We had this very dynamic atmosphere [and] we had this triggering mechanism that was the cold front," he said.
When those factors came together it created two rare outcomes. First, it was only the second EF-4 tornado -- twisters that pack winds between 166 and 200 mph -- to hit Southern Indiana since 1974. The other clipped the corner of Orange County in 1990.
Secondly, it created a powerful tornado during winter.
"Usually, if you see that in April and May," he said, when severe weather is much more commonplace.
The weather service said Tuesday a single, multivortex tornado plowed through 49 miles of Southern Indiana and Northern Kentucky, killing 10 people along its path through New Pekin, Henryville, Marysville and Chelsea before it crossed the Ohio River near Bedford, Ky.
The weather service office in Louisville completed posting its survey results online from the supercell that spawned the tornado that first touched down near Fredericksburg about 30 miles northwest of Louisville, and finally ended 49 minutes later north of Bedford, about 35 miles northeast of Louisville.
It killed a family of five in a mobile home in the New Pekin area, a man near Henryville and four other people near Chelsea. At its strongest, winds reached 175 mph.
FORECASTING & FACEBOOK
Callahan said forecasters knew rough weather was in store days in advance.
"We knew it was going to be bad," he said, but the location was the question. "There`s no way anyone can say where it would hit."
Indeed, forecasters were predicting severe weather about three days before it happened. Back in 1974, he said, meteorologists could typically only predict such outbreaks no more than a day or so in advance.
The better forecasting is a result of better data collection, faster computers and a better understanding of how weather works, Callahan said.
Further, as the forecasting has improved, so too has the process of getting the word out.
"The warning system has improved tremendously," he said.
During Friday`s storm, the Weather Service was getting video almost as it was happening. Further, residents were taking to Facebook and Twitter, reporting and posting pictures of what they were seeing.
In 1974, a lot of people didn`t know about it until they saw it, Callahan said.
Social media was also helpful in getting things organized after the storm hit. Rich Cheek, pastor at Henryville Community Church, said people around the region were tweeting and using Facebook to get in touch with him. He was using those sites to get directions to volunteers, get people in the right spots and let them know what was needed.
"Social media has been unbelievable," he said. "What you see is a result of social networking at its very best."
WHAT`S TO COME
Last year was a record-breaking year for tornadoes considering major outbreaks that tore through Joplin, Mo., Tuscaloosa, Ala., and other locations.
In an interview Friday, Weather Channel Meteorologist Jim Cantore said the mild winter didn`t allow the Gulf of Mexico to cool down as much as normal, something that could compound the severe weather outlook this spring. This year has already been rough, with Friday`s being the second tornado outbreak in Clark County in only three months. A much smaller tornado passed through Clarksville and Jeffersonville in January.
Callahan said it`s impossible to say whether the recent outbreaks are a sign of things to come.
"I hope not," he said. "We hope that things don`t get any worse."
Click here for comments or suggestions.
News submitted by WeatherBug users
WeatherBug Featured Content
Be Prepared, Know Before
Get faster alerts and better forecasts from the exclusive neighborhood-level WeatherBug network.Learn More