City of Boulder is warning residents to keep children and animals away from harmful blue-green algae that has been spotted in Wonderland Lake and Thunderbird Lake. This means that there is no swimming, wading, boating, or animals allowed in this water. Fishing is still allowed, but city officials warn that any fish caught should be thoroughly cleaned and guts should be discarded of.

Blue-green algae, also known as cyanobacteria, grow during the summer in slow-moving lakes or ponds. Some cyanobacteria species can produce cyanotoxins during algal blooms which can be harmful at elevated levels if ingested by dogs, wildlife and humans, or during wading and other recreational contact with water.

According to the Colorado Department of Public Health and Environment, harmful algae often has the following characteristics:

  • May look like thick pea soup or spilled paint on the water’s surface.
  • Can create a thick mat of foam along the shoreline.
  • Usually are green or blue-green, although they can be brown, purple or white.
  • Sometimes are made up of small specks or blobs floating just at or below the water’s surface

Harmful algae blooms will not have:

  • Long, stringy bright green grass strands that feel either slimy or cottony.
  • Mustard yellow (this probably is pollen).
Kaylee was raised (but not *technically* born) in Colorado. She graduated from Regis University with a bachelor of arts in English. During her time at Regis she worked as a teaching assistant in a freshman classroom setting and in the writing center helping students on a variety of topics. While there, she discovered Cura Personalis, or care for the entire person, leading to her love of feminism and desire for equal rights for all. Kaylee is the managing editor for AboutBoulder, OnDenver, and a key member of the OnMetro team, launching this platform in cities across the United States.