Summertime fun is being put on pause for swimmers that frequent Patterson Lake.
The culprit? Blue-green algae that is dangerous for people and animals.
"We've never had anything recorded like this before. late last summer is when we noticed some things like it is this summer, but not to the level of what it was. So that's why we got the state health department involved," says Matt Mack, facilities operation manager, Dickinson Parks and Rec.
The North Dakota Department of Health found two to nine times the recommended safe levels of toxins around the boating ramp, and the swimming area.
"There's definitely areas of the lake where you can tell that it's extra scummy. You can see foam in the water. It looks extra thick in the water. And that's what you really want to avoid going into," says Mack.
If consumed, the blue-green algae can cause flu-like symptoms, numb lips , dizziness, rashes and hives .
Mack says the appearance of the blue-green algae may be due to lower water levels, heat and lack of moisture.
But it is uncertain when people can begin using the lake again.
"It's hard to tell at this point in time how long it's going to take. It all has to do with the amount of moisture that we get and how much water is in the lake," says Mack.
The health department says anything from the wind blowing algae, to cooler temperatures can lower the level of toxins in the lake.
Until further notice, swimming is discouraged and boating should be done with caution.