Janesville45.1°

Storm was weak tornado

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ANN MARIE AMES
June 25, 2009
— The National Weather Service is calling it a tornado, although it was a very weak one.

Try telling that to Mary Jasper's porch.


Just after 8 p.m. Tuesday, a twister likely spun up over Clear Lake and hit the south shore of the lake at Blackhawk Campground, said Rusty Kapela, meteorologist with the National Weather Service out of Sullivan.


It ripped the screened-in porch neatly off Jasper's trailer at 3407 Blackhawk Drive. The tornado lifted the porch over the roof and dumped it in a heap on the other side.


It struck at about 8:08 p.m., according to reports from neighbors.


No one was home or hurt in the incident, Jasper said. She had been playing bingo at the Empty Platter, a bar and restaurant on the campgrounds.


"Nobody was hurt," Jasper said. "That's what's important."


Even the siding and the windows on the trailer were left intact.


Jasper, who lives in Indianpark, Ill., has spent summers in Blackhawk Campgrounds for 25 years and owned the trailer for 10.


Her trailer survived last year's flooding. The high water forced out trailers closer to the water, Jasper said.


But the five-minute storm was too much for the porch, Jasper said.


It was the damage to Jasper's porch damage that tipped the scales for Kapela. He was working Wednesday morning to figure out whether the storm produced a tornado or straight-line winds.


Kapela worked his way around Clear Lake, looking for damage and talking to property owners.


The "lifting" action of the wind and the extremely localized damage told Kapela that the winds were part of a tornado rather than the straight-line variety.


"I see a lot more evidence of a tornado than straight-line winds," Kapela said.


Straight-line winds likely would have damaged several structures at once, Kapela said.


Sometimes, straight-line winds pick up twigs and debris and carry them vertically through the air, tricking non-trained spotters into thinking they've seen a tornado, Kapela said.


Kapela labeled Tuesday's storm an "EF0" tornado. That stands for "enhanced Fujita scale zero," or the lowest rating on the scale used by meteorologists to measure tornados.


EF0 storms contain bursts of wind between 65 mph and 85 mph. Kapela said Tuesday night's tornado likely had winds in the 65 mph range.


An EF5 tornado—the highest on the scale—can have wind bursts between 200 mph and 234 mph.



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