Swimmers warned to avoid Lake Nokomis over blue-green algae advisory

Swimmers are being warned to stay away from a popular Minneapolis lake ahead of a warm weekend.

The Minneapolis Parks and Recreation Board issued a hazardous algae advisory for Lake Nokomis' Main Beach and 50th Street Beach due to blue-green algae.

The board found the lake to have levels of microcystin, a chemical the blue-green algae can produce, exceeding state guidelines for safe swimming. It will re-sample and reopen the beaches when bacteria levels are back within state guidelines.

The Minnesota Department of Health says blue-green algae can cause symptoms like vomiting, diarrhea, rash and headache. Symptoms can begin several hours to two days after exposure. Though it can make humans feel ill, it can be deadly for dogs.

Health officials say to avoid water that looks like "pea soup," blue or green paint, or that has a scum layer or puffy blobs floating on the surface.

The Minneapolis Parks and Recreation Board's website has a map showing water quality advisories for lakes across the city. Bacteria levels are monitored on a weekly basis.

Lake Nokomis is the only Minneapolis lake with a water quality alert as of Thursday night.