Minneapolis Park Board warns of harmful algae bloom on Cedar Lake

The Minneapolis Park and Recreation Board are warning people of a likely harmful algae bloom on Cedar Lake that could make humans and animals sick. 

Concerns over the algae started as soon as the ice went out in late March, revealing a Cedar Lake that people who live and walk in the area did not recognize. 

Keith Prussing, longtime president of the Cedar Lake Park Association, said the brownish color—a paint-like surface at times—alarmed a lot of people and for weeks there have been email chains and Nextdoor threads about it. 

The park board confirmed the algae bloom currently present on Cedar Lake is likely blue-green algae, which is toxic. Symptoms generally begin anywhere from two hours to up to two days after exposure and include vomiting, diarrhea, rash, eye irritation, cough, sore throat and headache.

Blue-green algae blooms can have a vibrant rust color and may look like spilled paint. They usually form in summer and early fall, but can occur at other times of the year under the right conditions. 

People who say the lake never looked like this right away in spring had a lot of questions and a lot of speculation and suspicion about the Southwest Light Rail construction on the canal between Cedar Lake and Lake of the Isles. 

A park board spokesperson told FOX 9 said they have found no reason to believe the algae bloom has any connection to the light rail construction. The park board says these algae blooms are naturally occurring, but anyone in or near the water needs to be cautions and pets should never be allowed in the lake. 

There is no way to tell if an algae bloom is toxic just by looking at it. The Minnesota Department of Health advises the following if you see an algae bloom on a lake: 

  • Don’t swim if you can’t see your feet in knee-high water (and wash off with fresh water)
  • Don’t let your dog drink or swim in the water. 
  • When in doubt, stay out