The National Weather Service received 42 reports of tornadoes in the south-central and southwestern portions of Hawkeye State (some of these are duplicate reports of the same tornado), part of an early outbreak. season which was worse than forecasters feared.
The most destructive tornado was described as “large and extremely dangerous” by the weather service, with a number of “particularly dangerous situation” tornado warnings issued. The parent rotating thunderstorm or supercell tracked for more than 150 miles, and it was likely Madison County’s main tornado could have been on the ground for more than an hour.
Madison County is home to the town of Winterset, which was devastated by the tornado. About 25 miles southwest of Des Moines, Winterset is the county seat and best known as the birthplace of actor John Wayne.
“This is the worst anyone has seen in quite a long time,” Ayala said at a predawn news conference on Sunday. “It will have an impact for many years to come.” The Weather Service tweeted that the damage near Winterset was consistent with a twister that would score at least a 3 on the 0-5 scale for tornado intensity.
Initial examination of photos and video from Winterset suggests that at least some EF3 tornado damage occurred late Saturday afternoon. NWS survey teams will be on site on Sunday to thoroughly investigate the damage and further assess a potential assessment.
— NWS Des Moines (@NWSDesMoines) March 6, 2022
Strong winds swept through an area along Carver Road, about three miles from Winterset. Ayala estimated that 20 to 30 houses on both sides of the road were destroyed, with the damage localized outside the town. State and local first responders from across Iowa were flocking to the hardest-hit areas to help with search efforts, Ayala said. Early Sunday, no one was forgotten.
Local volunteers and churches have stepped in to provide shelter to displaced people in Iowa. Ayala praised the community for its unity but urged people to stay away from damaged sites to give space to those who had lost loved ones or their homes.
“We are a small community, but we take care of each other,” Ayala said. “We had many volunteers who came to help us. They are caring. And we will rebuild, but we need time to come together and heal.
The tornado was spotted by the weather watcher at Des Moines International Airport, where all air traffic was briefly halted and travelers were evacuated to underground shelters. The storms left thousands of residents without power on Saturday evening.
Iowa Governor Kim Reynolds (right) issued a disaster proclamation for the region Saturday night to divert state resources to cleanup and recovery efforts. “Our hearts go out to everyone affected by the deadly storms that tore through our state today,” she said.
“Kevin and I join Iowans in praying for those who have lost their lives and those who have been injured. Our hearts are hurting during this time, but I know Iowans will step up and come together to help in this time of need. They already are,” Reynolds added.
Large hail and winds exceeding 80 mph accompanied the severe weather outbreak, which also affected northern Missouri, northern Illinois, southern Wisconsin, northern Indiana and western of Ohio, before the storms dissipated overnight. Another round of severe thunderstorms, including the possibility of tornadoes, is possible Sunday from northeast Texas to southern Ohio, with northern Arkansas and southern Missouri most at risk.
Saturday featured an environment characterized by extreme amounts of spin, albeit limited instability, or “juice” for storms. Southerly winds preceding an area of low pressure brought temperatures into the 60s and a hint of humidity. Although this would not normally have resulted in terribly robust storms, the exceptional change in wind speed and direction with height meant that any clouds that grew high enough were subject to strong rotations.
After a round of raucous noontime “appetizer storms,” four supercells rapidly grew in southwestern Iowa east of the Missouri River around 3 p.m. Brief and intermittent tornadoes touched down, including near the town of Emerson, Iowa, in Mills County. Before long, the cells began to fuse and interfere with each other despite producing the occasional spin-up.
This is when the southernmost storm cell in the line began to intensify. Often the southern storm becomes the strongest, as it has no neighbors to the south to cut off its supply of warm, moist air, giving it the fuel to strengthen markedly.
The storm first took on an ominous appearance as it passed near Corning in Adams County along State Route 34 around 3:45 p.m. when it began exhibiting a “demarcated weak echo region,” or hole. donut, on the radar. A void appeared where rain could not fall, commensurate with a strong updraft, potentially tornado, suspending precipitation. A tornado warning was in effect. There were several reports of a brief tornado touchdown south of Corning.
The storm continued to move northeast as warnings spread to Adams and Adair counties. Shortly after 4 p.m., “a confirmed tornado was located near Green Valley Lake,” the Des Moines Weather Service warned. It was moving rapidly northeast at 45 mph. A “peak hail” signature was seen on radar as the storm moved across the Orient, where storm chasers reported hail nearly 3 inches in diameter that shattered windshields.
Reports said the tornado was still on the ground at 4:10 p.m., when a new tornado warning was issued downriver for the town of Winterset. The tornado was still confirmed at 4:25 p.m., indicating that it was either continuously or nearly continuously on the ground.
The rotation tightened significantly just before 4:30 p.m., and the tornado hit Winterset at 4:34 p.m. Southeast portions of the Des Moines metro area were included in a new tornado warning at 4:34 p.m.
The tornado then passed north of Patterson near Frahm Concrete Construction and Lyon Enterprises at 4:55 p.m., crossed Interstate 35 between Bevington and Cumming at 5:00 p.m., then strengthened further hitting Norwalk at 5:08 p.m.
At 5:12 p.m., the tornado struck the Interstate 65 interchange near Exit 70 along Southeast 14th Street. Neighborhoods just north of the split of Highway 65 and Highway 5 were next at 5:18 p.m., including places such as Lake Avon, Carlisle Sports Complex and Army Post Road from the southeast.
The wedge tornado remained intact as it crossed Highway 163 around 5:30 p.m. before crossing Interstate 80 at 5:47 p.m. The tornado may have lifted briefly northeast of Newton and northwest of Kellogg around 6:00 p.m.
Shortly after 6 p.m., multiple reports were received of a “large and extremely dangerous” tornado, and it was likely on the ground between 6:04 p.m. and about 6:30 p.m. as it moved through Poweshiek, Tama, Marshall and Jasper counties. Then the traffic briefly re-intensified and settled again around 6:40 p.m. between Toledo and Elderboro, before the storm finally dissipated.
A number of additional tornadoes, some large, touched down in southern Iowa, leaving behind major damage. Several sets of “twin” tornadoes were seen in Lucas and Wayne counties in south-central Iowa.
Unusually strong event
In total, the tornado that passed through Winterset was likely grounded continuously for an hour and 40 minutes, assuming it did not lift between confirmation near Green Valley Lake and crossing Interstate 80. It probably traveled over 70 miles. Additional tornadoes were confirmed after the storm passed northeast of Interstate 80, so the “tornado family” may have lasted longer than two hours.
While the wind dynamics were certainly favorable for a high-end tornado, confidence in this outcome was low due to the low instability present. The National Weather Service Storm Prediction Center had rated only a 2 in 5 level of “slight chance” of severe weather, even writing that the risk of major tornadoes was “low” until the morning of the event, when he upgraded the risk to level 3.
While tornadoes have become common in Iowa in the spring and summer, intense tornadoes are very unusual at the start of the calendar year. Only once before, in January 1967, had tornadoes as strong as Saturday’s hit the state earlier this year. That day, one EF4, two EF3, and eight EF2 tornadoes swept through southeast Iowa.
Late last year, an unusual wave of late fall tornadoes also caused extensive damage in Iowa. That December outbreak had more than 60 tornadoes, including 21 rated EF2, setting a daily record for Iowa. The tornadoes in western and central Iowa that day were the first recorded in December. But no twister in this outbreak was as strong as Saturday’s, which was likely at least an EF3.
The most recent tornado as intense as Saturday’s hit Iowa last July. EF3 tracked sparsely populated parts of the state, and no one was killed or injured. If damage surveys confirm the latest tornado was stronger than originally predicted, it would be the first EF4 tornado in the state since 2013.
That year, an unusual October outbreak spawned a violent tornado in northwestern Iowa. This tornado affected few population centers and no one was killed or injured. Saturday’s storm brought about the first deadly tornado in Iowa since May 2019 and the first to kill as many in the state since a disastrous EF5 tornado killed nine people in May 2008.
Storms are expected to erupt again Sunday afternoon and overnight as a new storm system developing in Texas spreads across the Midwest. The Weather Service declared a 3 out of 5 “enhanced” level of risk for severe storms from northern Arkansas to southeast Missouri. A level 2 out of 5 general risk for intense storms covers the surrounding area from northeast Texas to central Kentucky and includes Little Rock, Memphis and Louisville.
The potential exists “for a few tornadoes and damaging winds,” particularly tonight and early overnight in parts of northern Arkansas and southern Missouri,” the weather service wrote. Severe weather could develop Monday as the storm system moves eastward with a high risk of severe weather from northern Alabama to West Virginia.
Jason Samenow contributed to this report.