Fierce storm batters boats, pummels historic park

Docks were shredded, boats were beached and even a historic amusement park couldn't escape the powerful wallop of a tree-snapping thunderstorm Saturday night.
(Photo by Brian Craig)

"In my 34 years in northwest Iowa, I've never seen such a fierce storm and have never had this kind of devastation on my farm," said Kate Whitrock who lives on an acreage east of Arnolds Park.

Straight-line winds estimated at up to 100 mph tore through the area just after 10 p.m. Saturday night. The storm was unusually persistent -- winds of 50-70 mph were measured a full 40 minutes after warnings were issued in Dickinson County.

Greg Harmon, meteorologist in charge for the National Weather Service, compared the peak gusts to the strength of an F2 tornado.

Dickinson County Emergency Management sounded sirens after radar from Sioux Falls, S.D., spotted some rotation near the Iowa-Minnesota border. They soon learned that straight-line winds would pose the biggest threat for campers, boaters and summer residents.

"It struck the Iowa Great Lakes area on a Saturday night in July on a day when we had 1,200 people run a marathon and triathlon," said Dickinson County Emergency Management Director Michael Ehret. "Campgrounds were full, hotels were full, there were people on the lake. To have that strike here without any injuries that we know of is purely a miracle."

Trees, and any cars or buildings nearby weren't as fortunate. Plastered leaves freckled Highway 71, the main corridor through the Iowa Great Lakes. A barn dating back to 1938 was damaged at the Whitrock farm. Four uprooted willow trees along the creek blocked the roadway at the location.

"They were 30 years old and close to 40 feet tall, and the wind just up rooted them and laid them over," she said. "A big tree, south of the barn, approximately 100-125 years old, also went down, partially uprooted, partially snapped. And I lost about 300 feet of 8-foot fencing."

Winds also targeted the 121-year-old Arnolds Park Amusement Park and its Legend, a rare wooden roller coaster. Debris dinged the famous structure, but it was back in operation, along with the rest of the park on Monday.

Park workers continued to assess damage Monday, but General Manager Scott Pyle knows two popular rides will be out of commission for the time being.

"We lost the Tilt-A-Whirl and the Spider," Pyle said. "They have pretty substantial damage."

He expects damage estimates to exceed $100,000. Pyle closed down the park about 15 minutes before sirens sounded in the county.

Water craft also sustained extensive damage: Boats got blown out of their hoists on the north end of West Lake Okoboji and wound up on beaches near Terrace Park on the south end.

"It just moved down along the lake," Ehret said. "The winds get on that lake and they can just sail across that water."

Ehret's assessment as confirmed by Harmon at the National Weather Service.

"There wasn't much frictional impact from trees, houses and things like that," he said. "I think the wind had some opportunity to even accelerate as it traveled across the lake."

Neighbors helped neighbors in The Landings, a residential area north of Gull Point State Park on the west side of West Lake Okoboji. There, some residents were without electricity for about 20 hours. Others had branches of toppled trees poking through their ceiling.

"All of the residents pitched in today to start clean up," said Jan Turner, who lives in the area. "A lot was accomplished, but a lot to do yet."

About 250 residents, many in the Lake Park area, were still without power Monday morning. Alliant called in crews from other regions to help restore electricity.

Ehret noted some extensive damage in incorporated Montgomery as well. The collection of residences is just west of Spirit Lake near the intersection of Highways 9 and 86.

"There were a lot of trees down and a couple of trees on houses in Montgomery," Ehret said. "There was a storage shed destroyed -- and of course as the trees came down, the power lines came down with them over there. West of Montgomery, there's about a mile-and-a-half worth of power lines that were simply pushed over by the winds. It just kept moving southeast. Triboji (on the north tip of West Lake Okoboji) took a real hard hit, with a lot of trees and branches down. All of the roads in Triboji were blocked."

County crews brought out payloaders to clear the way for Emergency Management in Triboji and Montgomery. City crews in Milford, Okoboji, Wahpeton and West Okoboji were doing the same. The winds knocked billboards over and shattered the signs of businesses along Highway 71.

Harmon said the storm had a couple of uncommon qualities.

"For nearly 40 minutes or more, there were winds probably gusting in excess of 60 mph in the Okoboji area, so that in itself is pretty unusual," Harmon said. "Most of the time, you get strong winds associated with a thunderstorm like this and they pass fairly quickly."

The 10 p.m. hour also is less than ideal for storms to get momentum, according to the meteorologist. Storms typically need the day's heat to build strength and early evening storms are usually more severe as a result. Harmon said the storm was a soaker at first, causing flooding in the Brookings, S.D., area before making its way to the southeast.

"We had all of the conditions," he said. "We had the very hot, humid weather that was across the area Saturday afternoon into Saturday evening. Then this particular storm developed right along a cool front that moved southeast across the area as it moved into northwest Iowa. It did weaken as it moved south into the Spirit Lake area, but still strong enough to produce the 100 mph winds."