Thursday storm hit some cities harder than others
High winds, some hail and at least one tornado combined to make for a turbulent Thursday afternoon in Dickinson County. Fortunately, no injuries were reported to the county emergency management. The storm swept in from the west a little after 5 p.m. Thursday and moved quickly through the region. Peter Rogers, warning coordination meteorologist with the National Weather Service in Sioux Falls, said a warm, moist mass of air ahead of an eastward advancing cold front caused the storm clouds to roll in as they did.
He said the storm front wasn't severe in its entirety. Rather, the meteorologist said there were pockets of intense activity along the storm's leading edge.
"It was interesting, because that line of thunderstorms first developed west of Sioux Falls, and the atmosphere that far west wasn't nearly as unstable," Rogers said. "As it moved farther east, it picked up strength and intensity and did become severe."
Dickinson County Emergency Management Coordinator Mike Ehret said crews were storm spotting as the system approached and information on what to expect was relayed to authorities. Both he and Rogers said the system intensified as it approached the Lakes Area. Ehret said monitoring stations clocked 40 mph winds in Lake Park and 50-65 mph winds near Milford.
"On one hand, it was good that it moved through as fast as it did, because it kept the rain amounts lower," Ehret said. "The flip side is, because it came through so fast, it had high winds with it that caused damage to the trees."
Data from the National Weather Service showed areas like Spirit Lake received around 5.85 inches of rainfall the week of the storm. Ehret said the rains softened soil throughout the community and likely contributed to the number of trees uprooted by Thursday's storm. Downed trees blocked southbound traffic along Highway 71 in two places in Milford, according to Ehret, and portions of the Perkins Restaurant sign in Milford were blown onto the ground below. He also said the VFW in Terril sustained some storm damage, and portions of its roof were caught in a power line.
One of the many uprooted trees in the region fell against the home of Irv and Pat Schnell in Milford. Pat said her husband was expecting trees to fall on the east side of the house, but neither of them heard the tree fall on the opposite side because the rain was falling so heavily on the metal portion of their roof. She said neighbors came to her back door later that night to see if she and her husband were all right — the front door was blocked — and she had no idea why they were asking.
"We were really lucky," Schnell said of the tree limbs. "If they would have been any farther, they'd have been through the roof. It's right against our picture window."
Farther east, Superior bore the brunt of what became a tornado. Ehret said the storm system intensified after passing the Lakes and formed what is called a bow echo, in which the leading edge of the storm swells, indicating very strong winds.
"They were kind of on the nose of that bow echo, so they got probably the strongest winds and what the weather service later determined to be an actual tornado," Ehret said.
Rogers confirmed the tornado was classified as a EF1 with top wind speeds of approximately 99 mph. He said the EF1 class is the second-lowest on the scale.
"If individuals experience a tornado, the vast majority of them are in those weaker categories, but that's not to say the stronger ones can't occur up in our neck of the woods either," Rogers said.
Ehret said it is difficult to sound warning sirens for such tornados, as they form somewhat quickly on the edge of severe storms.
"We were under the severe thunderstorm warning, and sometimes people don't take those thunderstorms seriously, because they think it's just a little wind and a little hail," Ehret said. "I just want to remind people to take those warnings seriously, because sometimes we get events like this."
The National Weather Service determined the tornado touched down on the south side of Highway 9 near Big Muddy Creek and crossed the road near the Green Plains ethanol plant, damaged the business' office, largely destroyed a garage in the city and exited the county between 140th Street and the highway before trailing off in Emmet County. All totaled, the funnel cloud traveled 3.9 miles in approximately 5 minutes, according to the weather service's data.
"Let's hope this is the last severe event of the season as we move into late September," Rogers said.
He said northwest Iowans can look forward to a change of pace with highs in the 50s and 60s expected for the coming days.