Forecasters have inspected the damage where strong winds hit a highly localized area in northwest Iowa after a heavy storm early Thursday. The estimated 80-miles-an-hour winds damaged one home in Rock Valley, while debris affected others nearby.
The phenomenon, called a “microburst," can happen when a thunderstorm dies down. Air rushes down to the ground and can heavily damage things in its way.
There was no warning issued before it happened. The National Weather Service in Sioux Falls, South Dakota is looking at drone footage and radar information to determine how it unfolded and what they could’ve done better to warn people, said Todd Heitkamp, the meteorologist in charge.
“So far, looking at the radar information and everything that’s before us right now today, we haven’t seen anything that would indicate to us that we would do anything different,” Heitkamp said, “but we’re not done looking. We’re going to continue to try to find that needle in the haystack.”
Heitkamp said the weather service put out information predicting storms and strong winds for the area. The service predicted winds would reach up to 40 to 45 miles per hour.
The burst touched the ground just outside of Rock Valley shortly before 3 a.m. Thursday, according to the National Weather Service. It likely lasted less than a minute, Heitkamp said, “Because there wasn’t any other damage throughout the entire town.”
Heitkamp said these microbursts happen more often in rural open country instead of near homes.
A preliminary survey determined the early morning damage in Rock Valley Iowa was caused by a microburst with winds up to 80 mph. The microburst significantly damaged one home on the west side of town, and debris from this home caused collateral damage to other homes in the area.
— NWS Sioux Falls (@NWSSiouxFalls) July 4, 2019