Tornado formed in Urbandale too fast for advance warning from National Weather Service

Urbandale residents learned the hard way during Monday's tornado that severe weather warnings and outdoor sirens are not perfect systems.

Sirens in the area sound automatically when the National Weather Service issues a tornado warning. But the weather service's Des Moines metro office confirmed to the Des Moines Register on Wednesday that it did not issue a tornado warning until five minutes after Monday's twister touched down at 5:37 p.m. in Urbandale near Meredith Drive east of Northwest Urbandale Drive.

Multiple residents on 80th and 82nd streets in Urbandale — where the EF1 tornado , with winds from 100-105 mph, did some of its worst damage — told the Register on Tuesday they did not hear warning sirens ahead of the tornado.

Justin Reese said his wife was the only one at their home on 82nd Street when the tornado tore through the neighborhood. He said she received no warning, and that the tornado arrived so fast that she was unable to take shelter in the basement.

"She didn't have time," Reese said. "I don't even think the sirens went off here, so she didn't know that anything like this was coming, which is pretty disappointing."

She was uninjured, but one of their cars and a backyard fence were damaged and four trees fell.

Ann Birdsley had just set dinner on the table for her and her son on 80th Street when it got "black as night" outside and her maple tree in the backyard started to bend sideways with the wind.

"And we said, 'We gotta get to the basement,'" Birdsley said. "The minute our feet hit the basement floor, this huge explosion" happened.

The family later discovered the "explosion" was the sound of a trampoline ramming against their dining room window.

Glass was everywhere, Birdsley said. The wind blew out other windows and part of their roof was whisked away. Their cat ran away, too.

Birdsley said they didn't receive a cellphone warning about the tornado until about 30 seconds after it tore through.

Karen Van Thournout was eating at home on 82nd Street with her family when her sister-in-law noticed the wind had picked up outside. They all got up to look.

"And then all of a sudden, it was just whoosh," Van Thournout said.

She said it was fortunate the family had recently chopped off 15 feet of a tree that toppled in their backyard and landed withing inches of their home.

"We just looked at each other and went, 'What just happened?'" she said.

It wasn't until after the tornado passed that they received the tornado warning, she said.

"I turned to my sister-in-law and said, 'Well, that was a little late,'" she said.

John Hoberg was in his living room on 82nd Street when he heard the "overpowering" sound of the tornado just before the trees in his yard started twisting in all directions. He said he did not hear sirens.

"It just all of a sudden came up. … I looked outside and I could see all the debris flying around. You could see the rotation," Hoberg said.

He had received a severe thunderstorm warning notification on his phone, but said that if he had received a tornado warning or heard sirens, he "would've gone down to the basement a little earlier."

The weather service issued severe thunderstorm warnings at 5:20 p.m. and 5:29 p.m. The first warning was for a storm moving east from an area near Minburn at 55 mph. The second was for a line of storms stretching from Haverhill to Urbandale, moving southeast at 45 mph.

When the first tornado warning was issued at 5:42 p.m. and the sirens were activated, the tornado was already halfway through its 10-minute journey southeast through the metro from Urbandale to Windsor Heights and northwestern Des Moines.

Hoberg said that despite the scare and the damage to his home, including a knocked-out TV dish, split and fallen trees, and a torn gate, he's grateful he and his three dogs stayed safe.

"I'm alive. You know, that's the most important thing," he said.

No injuries were reported from the storm, although one person in Urbandale apparently was injured during the cleanup.

More: 'We'll get through it': In Des Moines, Urbandale, residents band together after tornado

Tornado developed faster than a warning could be issued

The tornado that touched down in Urbandale was from a storm that was part of a forming derecho — a fast-moving line of thunderstorms that can produce high winds.

It moved more quickly than the weather service could respond.

"When it evolved to produce a tornado, that all moved along pretty quick," meteorologist Cory Martin said Wednesday.

Martin said radar indications of debris the tornado had picked up prompted the office to issue the 5:42 p.m. tornado warning. The warning said the tornado was "located over Merle Hay Mall, or near Urbandale, moving east at 45 mph."

A switch from "radar indicated rotation" to "radar confirmed tornado" produced another tornado warning at 5:45 p.m. , It said the tornado was "located over Drake Stadium and Knapp Center, or near Des Moines, moving east at 45 mph."

The tornado was confirmed at 5:44 p.m., according to the warning notification.

Udell Mentola, chief of the Westcom Dispatch Center, which dispatches police, fire and emergency medical services for the cities of Clive, Norwalk, Urbandale, Waukee, West Des Moines and Windsor Heights, said Wednesday that the outdoor sirens are automatically activated by the warnings.

Once a warning is received, Mentola said, it's only milliseconds until the sirens activate. He added that a manual override to activate sirens also is available if a funnel cloud is observed on a video monitoring system or reported from a trusted source. The system is tested weekly.

Mentola said the sirens are meant to serve as warnings for people outdoors in areas such as parks, and that people indoors should not rely entirely on them. He encouraged residents to make sure they are able to receive warnings from other sources, including TV, phone apps and weather radio.

The Des Moines metro has experienced three damaging tornadoes in the past four months, including Monday's. Martin, the weather service meteorologist, said that’s "not unprecedented" but "certainly not something we see every year."

An EF2 tornado touched down May 21 in Johnston and continued 41 miles through Polk and Story counties before dissipating near Zearing. It formed near Johnston High School, causing damage that forced the cancellation of classes the following day.

Another EF2 tornado on April 26 caused extensive damage in Pleasant Hill .

More: Despite deadly tornadoes, no place in Iowa requires storm shelters in homes, apartments

Phillip Sitter covers the western suburbs for the Des Moines Register. Phillip can be reached via email at psitter@gannett.com or on X, formerly known as Twitter, at @pslifeisabeauty.

Virginia Barreda is the Des Moines city government reporter for the Register. She can be reached at vbarreda@dmreg.com.

This article originally appeared on Des Moines Register: Tornado formed in Urbandale too fast for advance warning from National Weather Service