Blue-Green alage bloom at Lake Harriet: When in doubt stay out

A blue-green algae bloom in Lake Harriet in Minneapolis could be harmful if ingested, the Minneapolis Parks and Recreation Board is warning. 

Algae blooms occur naturally, but park officials are concerned with the current bloom because it is a mix two types of algae, blue-green and filamentous. 

The blue-green algae can produce cyanotoxins, which can be harmful to humans and animals if ingested. 

Blue-green algae has been reported on Lake Harriet in Minneapolis.

The Minnesota Department of Health (MDH) is reminding people there is no way to tell if an algae bloom is toxic by looking at it. 

RELATED: Now is prime time for toxic algae blooms that can sicken people, kill pets

MDH advises three steps to stay safe:

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

Algae are a natural part of lake ecology, and algae blooms can happy any time of year under the right conditions. Springtime algae blooms can occur as lake conditions change quickly, due to large amounts of nutrients from snowmelt, warming water and shifts in weather. 

The city and some Minnesota counties test and track water quality at local beaches. Seasonal water quality testing at beaches in Minneapolis begins in June, however advisories for Lake Harriet are currently posted on the city's Lake Water Quality Status map.