SHERWOOD, Wis. (WLUK) -- If you’re heading to High Cliff State Park this weekend, you may not want to take a dip in the lake. That's because residents have reported seeing blue-green algae on Lake Winnebago, and experts say the north end of the lake is getting the worst of it.
Before you could even see it, you can smell it. The second you step foot on the marina at High Cliff, the stench is overwhelming.
“The odor is similar to manure, especially when it kind of wipes up or glides up onto the side of the water -- the edges of the water,” Calumet County Health Division manager Bonnie Kolbe said. “You really notice it then."
The culprit? Cyanobacteria. It causes the blue-green algae blooms on Lake Winnebago.
Officials say if you're close enough to smell it, you're close enough to get exposed to it, and the windier it is, the more at risk you become.
The thick, green film can be toxic.
"People can become ill from it,” Kolbe explained. “It can produce symptoms, such as nausea, vomiting, respiratory symptoms, skin irritations, gastrointestinal symptoms -- you know, things like that."
Satellite images show where it’s currently blooming, with the areas in red seeing blue-green algae the most.
And the warmer it is, the worse the bacteria gets.
Blue-green algae forced the Wisconsin Department of Natural Resources to close the beach at High Cliff State Park on Friday.
"I haven’t received as many reports of severe algae blooms, compared to what we saw last year, but it's becoming more intense, especially in Lake Winnebago,” said Korin Doering, Winnebago Waterways program coordinator.
Doering also said there are steps homeowners can take to reduce the bacteria from spreading.
"People can do things like pick up their pet’s waste and divert water from running off into their driveways or the streets,” she said. “Instead, let in infiltrate on their lawns or in their garden.”
Last year, it was clear that Lake Winnebago was infested with widespread blue-green algae near Menasha. But it's not always easy to tell regular algae, from potentially harmful blue-green algae.
So, one good rule of thumb Kolbe and other experts say you should follow: "When in doubt, stay out!"