Wicked wind rewrites the history books

Wicked wind rewrites the history books

May 1st, 2011 by Pam Sohn in News

BY THE NUMBERS

April 26-28 2011 tornado outbreak

• 288 tornadoes from 8 a.m. April 26 to 8 a.m. April 28

• At least 344 deaths

• Previous record was 148 tornadoes on April 3-4, 1974, with 308 deaths.

• Standing record is 454 deaths in an outbreak on April 5-6, 1936.

Source: National Oceanic and Atmospheric Administration


DEADLY TRACK

A single EF4 tornado with winds of 175 mph tracked into Tennessee from Catoosa County and traveled 35 miles through Hamilton, Bradley and Polk counties.

It was a day like no other.

When Wednesday's wicked weather spun through the tri-state area, it rewrote the record books.

At no other time in recorded history has the region had a dozen - possibly several dozen - tornadoes in one day.

This morning, as tri-state residents in the Chattanooga area mourn nearly 80 lost lives, the nation is crying for all 344 people who died in 288 tornadoes that have become known as the Super Outbreak of April 2011 - the worst storm the South has ever seen.

Hamilton County alone had seven tornadoes that didn't just touch down - they tracked.

One ripped the earth for at least 35 miles from Ringgold, Ga., through Hamilton and Bradley counties and into Polk County. Along the way the EF4 twister killed at least 18 people and injured hundreds.

The deadly three-day swarm of tornadoes rode waves of storms that exploded out of unstable air over Mississippi with a speed that surprised veteran forecasters with their storm computer models.

The storms marched across six states and replaced the Super Outbreak of 1974 as the busiest and third-deadliest outbreak in the nation's history.

The 1974 outbreak carried 148 tornadoes and killed 308 people. The Tri-State Tornado of Wednesday, March 18, 1925, was the deadliest tornado in U.S. history with 695 confirmed fatalities

Wednesday's storm and the 1974 outbreak were fed by a La Nina wind that simply rubbed the normal southeastern weather pattern the wrong way.

"This storm system carried with it very strong winds aloft in the atmosphere just above the ground level, about 2000 feet up," said Tim Troutman, a warning coordination meteorologist with the National Weather Service, as he surveyed damage here Friday.

"With those aloft wind speeds upwards of 70 and 80 miles an hour, all it takes is a downdraft or downrush of wind to bring that down to the ground level. And the way the storm system was oriented to the area, it was causing winds to come into the area from the southeast, [rather than a normal flow from the southwest]. When that happens, it causes more rotations in the winds in the atmosphere," Troutman said.

COUNTING THE TOLL


Bradley County

• Five tornadoes, three still unconfirmed

• Nine dead, 89 injured

• 260 homes destroyed, 180 with major damage, 127 with minor damage, 120 homes affected, 10 businesses damaged

• 6,235 Cleveland Utilities and Volunteer Energy Cooperative electric customers still without power.

Tracks confirmed:

• An EF1 with winds of 100 mph traveled about two and a half miles from the southeast of the county just into Cleveland.

• EF4 that tracked in three counties


Hamilton County

• Seven tornadoes, two still unconfirmed

• Nine dead, about 300 injured, 474 homes damaged

Tracks confirmed:

• An EF2 with winds of 110 mph traveled about one and a half miles through Lookout Valley from the foot of Lookout Mountain to the Tennessee River at 8:55 a.m.

• An EF1 with 90 mph winds touched down near Ooltewah/Georgetown and Ooltewah/Ringgold roads at 6:16 p.m.

• An EF1 with winds of 90 mph traveled two miles in Red Bank near Ashland Terrace at 9:04 a.m.

• An EF0 with winds of 70 mph traveled about a half mile near North Hickory Valley Road in Harrison at 9:08 a.m.

• An EF4 that tracked in three counties


Catoosa County

• Seven dead, 30 injured

• 100 homes damaged or destroyed

Tracks confirmed:

EF4 with 175 mph winds in Ringgold and Cherokee Valley


Dade County

• Two dead, 12 injured

• At least 18 homes damaged or destroyed

• An EF3 in Dade and Walker counties with winds of 150 mph. This storm crossed Alabama state line just after 5:30 p.m. and lifted just west of Fort Oglethorpe just before 6 p.m. It traveled 18 miles on the ground in Georgia.

• An EF1 in Dade County with winds of 100 mph at 8:40 a.m. tracked for seven miles. Several homes and an elementary school had minor damage.

• An EF1 with winds of 110 mph at 7:50 p.m. came from Alabama and tracked three miles from near Fox Mountain to Rising Fawn.

The perfect storm

A La Nina event represents unusually cold temperatures in the eastern Pacific Ocean. When the jet stream picks up that coolness and slams into warm, moist Gulf Coast air, things can get messy.

The pattern may ebb and flow in the Southeast for several more weeks, Troutman said. Records show that May normally is the Southeast's most active tornado month.

"In this region right now we're in later stages of the La Nina weather pattern," he said. "We think the La Nina pattern here will slowly subside toward the summer."

In the meantime, expect a more active weather pattern than normal.

"The Super Tuesday tornado outbreak of 2008 also was during a La Nina climate pattern period," Troutman said.

In that 12-hour outbreak on Feb. 5-6, the weather service confirmed 87 tornadoes in nine states with 57 fatalities in four states, including Tennessee and Alabama.

EPB President Harold DePriest has noticed a change.

"We have had more tornadoes in the past two months than we've had in my previous 40 years combined at EPB," he said. "It looks like this spring we're having a gracious plenty, as my grandmother used to say."

Looking for answers

Knowing the history and proving the patterns are what make the work of Troutman and other National Weather Service survey teams so important for future forecasts.

Like forensic examiners eyeing a crime scene, Troutman and meteorologist Eric Holweg on Friday surveyed splintered, twisted trees that fell in all directions in Lookout Valley.

He noted sheet metal dangling from a snapped limb 60 feet in the air above Kelly's Ferry Road. He studied missing roofs, collapsed walls and stray insulation.

With a quick nod, Troutman raised his notebook and made a notation before announcing to Holweg: "This was EF2, with winds about 125 mph."

"We want to be able to identify tornadoes. And we want to better document the fact that the Tennessee Valley region is prone to tornadoes," he said.

Troutman calls the area a bona fide tornado alley.

"In some cases there are more tornadoes that occur in Dixie Alley in certain months of the year than in the main [Midwest] tornado alley," he said.

Deeper research means more painstaking comparisons of weather outbreaks with their earlier computer-modeled forecasts.

But the work can show whether certain counties may be more prone to tornadoes and help their officials seek state and federal assistance to improve warning, planning and response, they said.

Living the horror

Chuck O'Mary, supervising the cleanup of several large trees that crashed into and around his daughter and son-in-law's Lookout Valley home Friday, said he would welcome improvements.

His daughter, Elizabeth Bowden, was dozing on the couch with her 2-month old twins Wednesday morning around 9 - just before that EF2 tornado laid waste to her neighborhood along Kelly's Ferry Road.

Bowden said she snapped awake when the power went off and the TV's droning stopped.

"I jumped up to look out the window, and when I saw how dark it was I thought, 'Oh, no!'" she said.

She grabbed her twins and huddled in the closet.

"I thought I was going to die," she said, swallowing a sob. "I was thinking, 'How can I fall on them and save them and not hurt them?'"

Staff member Dave Flessner contributed to this story.