Anchoring systems are usually the point of failure when tornadoes strike mobile homes

It's a common, almost expected, outcome in the wake of a powerful tornado:

Mobile homes turned inside out and death.

Easter Sunday night, seven of the 10 people killed by tornadoes in the tri-state area died in manufactured or mobile homes that two experts say were not equipped to withstand a powerful twister's winds.

Those who survived counted themselves lucky.

In Murray County, Georgia, a few days after the tornado struck, Patricia Watson sat at the edge of her bed and leaned heavily on a cane with her right hand. The bruises on her arms, both sides of her head and cuts and abrasions on her back left her looking like she'd been in a fight with a bear.

Watson ended up with three stitches on the inside of her ankle and 18 on the outside for a cut.

"It hit us like a freight train," Watson told a Times Free Press reporter last week. "Our trailer flipped over four times and it threw me 25 feet."

First responders found Patricia Watson unresponsive and far away from her husband, Chris Watson. The couple had taken cover together in a closet before the tornado hit.

According to National Weather Service records, at least eight mobile homes were destroyed by an EF2 tornado that roared through two Murray County communities where the deaths occurred a few hundred yards apart.

About 20 miles to the north the same night, an EF2 tornado that formed directly over downtown Cleveland, Tennessee, touched down on the east side of town where mobile homes are scattered with traditionally built homes on close-knit residential lots along winding one-lane roads. Bradley County EMA officials say 54 mobile homes in the area sustained damage. It was unclear how many of those injured lived in mobile homes.

Manufactured homes and tornadoes are a deadly mix, but the companies that make them have improved the structures' storm-worthiness to a great degree, said Stephen Strader, assistant professor of geography and environment at Villanova University in Pennsylvania.

While the deaths in Murray County happened in two clustered manufactured home communities that weren't there in the 1990s, the number of mobile homes in a square mile drawn around those communities now totals "more than 300 mobile or manufactured homes" that Strader said came from a "massive explosion" of manufactured home growth across the Southeast in recent decades.

An associated problem is that the odds a tornado will hit a mobile home are higher in the South because a majority of them are scattered alongside traditionally built homes, like those in East Cleveland, and anchoring systems installed by third-party companies differ and aren't often scrutinized by officials, Strader said.

According to 2018 data from the Manufactured Housing Institute, 22 million people in the U.S. are living in manufactured homes. Institute statistics show there are 124 manufacturing plants in 24 states across the country with 10 of them in Tennessee, nine in Georgia and 12 in Alabama. Texas has the most plants at 20, the institute's statistic show.

Manufactured homes adhere to Housing and Urban Development codes established in 1976 and revised in the 1990s that include updated standards for wind resistance, according to the institute.

"When you look at the superstructure of a mobile home, the manufactured housing industry will tell you that the box is stronger than ever before and that is true," Strader said.

"The problem is that when these mobile or manufactured homes are installed, the anchoring is the first thing that gets neglected," Strader said. "A lot of times the anchoring is insufficient, or what anchoring that is there or the thing that holds the mobile home to the ground has deteriorated over time or was never up to high enough standards to begin with."

When anchoring systems fail at the base of the superstructure, mobile and manufactured homes are "thrown and lofted and tossed, and that's where fatalities are occurring," Strader said. "We saw that case with every single fatality in a manufactured home in Murray County. The part that failed in those manufactured homes is outside the structure where it's tied to the ground."

David Roueche, an assistant professor of structural engineering at Auburn University in Alabama, visited the tornado strike zone in Murray County where deaths occurred in the two manufactured home communities just a few hundred yards apart.

Roueche said anchoring system regulations are outdated and insufficient. Federal requirements for anchoring systems' resistance to wind are divided into Wind Zone I, Wind Zone II and Wind Zone III. Requirements for the Chattanooga region fall into the Wind Zone I category, established in 1976, one Roueche says should be updated or simply done away with. Wind Zone III applies to coastal areas of the Gulf and East coasts.

Federal Emergency Management Agency personnel agree the problem lies with manufactured homes' anchorage failures that can destroy a home even when there is no direct wind damage to the home itself, according to a 2007 FEMA report, "Understanding and Improving Performance of New Manufactured Homes During High-Wind Events."

For homes designed to be installed in Wind Zone I areas like the Chattanooga region, the design criteria in the standards require only diagonal - or frame - ties to be secured to the main frame members, usually two steel I-beams under each section, the FEMA report states.

For homes designed to be installed in Wind Zone II areas, which are near or on the coast, the standards require that homes be additionally provided with vertical wall ties at each frame tie location or anchor.

In the hurricane-blown state of Florida, statutes also require longitudinal ties to resist manufactured home movement along the length of the home, the FEMA report states.

In most manufactured homes, anchorage is provided by ground anchors and steel straps. Ground anchors consist of a steel shaft and one or two steel plates that are augured into the earth, according to FEMA. Most ground anchors contain heads specifically designed to accept the steel straps that connect the anchor to the home's frames and wall ties with ground anchors installed at, or near, a vertical angle to increase their resistance to lateral movement or displacement.

"Wind Zone II homes have proven to perform substantially better than pre-1994 homes in hurricane zones," Roueche said.

Roueche said an update would not have to change much in terms of regulations.

"You could gradually phase it in over a couple-year period perhaps or set a target three to four years out that all new sales be Wind Zone II," he said.

"The superstructure of manufactured homes are built in a factory, in a controlled environment, with inspections to meet the HUD standards," Rouesche said.

Stiffening anchoring requirements would help the now-sturdier manufactured homes stay connected to the ground.

"Once a home leaves the factory, homes are installed by installers, in an uncontrolled environment, with very little if any oversight," he said.

"The anchorage is either relying upon pan systems, which have no capacity beyond design, if they even meet design under various soil conditions," Roueche said. "Or the anchorage is relying upon ground anchors and metal straps, and the ground anchors have been shown in published literature to not provide enough capacity to meet regulation."

Photo Gallery

Mobile homes in tornadoes

Roueche said at least two of the homes destroyed in Murray County used a "pan" system, which basically consists of struts attached to a flat pan with four attachment points in the corners that sits directly on the ground. Most others used strap and anchor systems, he said.

The "pan" system relies on the soil underneath to resist sliding back and fourth, he said.

"The problem is there really is no anchorage. It's stabilizing the home but it's not anchoring the home," he said. "As soon as you get winds that start to lift or rock the home, it's just gone."

Anchorage failures aren't only dangerous in manufactured homes, Roueche said.

The March 3 tornadoes that struck Nashville "showed again that anchorage matters in site-built homes, too," he said. "Anchorage issues are magnified in manufactured homes, though, because they are lighter than most site-built homes."

Roueche recommends that manufactured and mobile home residents inspect their anchorages every year for corroded or loose straps, and to consider adding more straps anchored in concrete with anchors longer than the standard of 32 inches.

Strader and Roueche said the time to look at making changes is now.

"Since Murray County, we've had another 10 people die in manufactured homes because of tornadoes in Mississippi, Georgia and Alabama," Strader said.

Until improvements are made, Roueche and Strader said residents living in manufactured and mobile homes should make a decision to seek shelter when the first tornado watch is issued, not when it's a tornado warning and time is too short.

"Have a safer place not in your manufactured home that you can get to quickly for safety, whether that's a church, neighbor's home, etc.," Roueche said.

That's what one mobile home park owner in Rossville, Georgia, did after he saw the devastation left by the April 27, 2011, tornado outbreak that killed hundreds across the South and nearly 80 in the tri-state area.

In the wake of that outbreak, David Roden, owner and resident of Mountain View Estates mobile home park in Rossville, Georgia, began studying a way to make himself and his mobile home park residents safer.

Roden did research on tornado shelters, visited shelter manufacturers and watched a shelter be installed in Pisgah, Alabama, before spending more than $100,000 to build a shelter for his residents in 2015.

He said that since 2015 the shelter has been used up to a dozen times, including twice on Easter Sunday 2020.

After having the shelter for five years, there's not much he'd change. Residents are already supposed to have weather radios, a requirement since the shelter was built.

"We're adding a TV to it so we can watch the local stations and the radar," he said. He also said he planned to work harder on making sure residents in his park are notified as early as possible - he purchased a service called "Weather Call" to use to alert residents - and he wants more of them to use the shelter when storms threaten.

"It's sort of like a seat belt," he said, "it's there to save your life, but it's up to you to put it on."

Mountain View residents Teresa Noel and James Perry both said the tornado shelter was a major reason they chose to live there.

Noel, 62, moved to North Georgia from Michigan right after Roden installed the shelter five years ago.

"When you live in the South it's a very real possibility, and mobile homes don't stand up very well in a tornado," she said. The fact that Mountain View had a shelter was a comfort, she said.

"I don't know what other people do that live in mobile homes," said Noel, who is one of the park's shelter key holders.

Perry, 67, said he and his wife, Audrey, 59, moved to the park from Virginia, where they had frequent experiences with hurricanes and tornadoes.

"Living in a mobile home, that's one of the things you have a concern about: If a tornado comes, do you have shelter?" Perry said. "The shelter was a big part of buying a home out here."

Noel and the Perrys were in the shelter Easter Sunday as the tornado outbreak unfolded.

"Easter Sunday was the third time we've been there," Perry said. He and his wife's mobile home is just 300 yards or so from the shelter, so it's a quick trip.

"We got in the habit of when they say there's a possibility, we pack our bags and put them in the vehicle," Perry said.

Noel, likewise, has a bag ready for emergency trips to the shelter.

Both Mountain View residents said they were grateful for Roden's effort to keep them safe, and Perry noted that Roden uses a golf cart to take elderly residents to the shelter.

Roden said the idea generated some interest from a few other mobile home park owners, including one in Kentucky, another in Texas and a man from Clarksville, Tennessee, who called Roden after Easter Sunday's outbreak to talk about shelters.

Meanwhile, the work to improve continues.

"We've known about this problem since the 1990s when it was first talked about, but we're just now getting to the point where data is starting to get better and we're really starting to understand the problems," Strader said.

"Now we're trying our best to come up with solutions."

Staff writer Patrick Filbin contributed to this story.

Contact Ben Benton at bbenton@timesfreepress.com or 423-757-6569. Follow him on Twitter @BenBenton or at www.facebook.com/benbenton1.