Blue-Green Algae Bloom Detected In Crooked Lake; City Issues Advisory
COON RAPIDS, Minn. — August 22, 2025 — The City of Coon Rapids has issued a public advisory after a blue-green algae bloom was detected earlier this week in the southeast area of Crooked Lake.
The Coon Creek Watershed District first alerted city officials to the bloom on August 18, prompting immediate water testing the following day. Results of cyanotoxin testing, received on August 21, showed toxin levels were within safety thresholds established by the Minnesota Pollution Control Agency (MPCA), meaning there was no elevated health risk at the time of sampling.
However, city officials caution that water conditions can shift quickly. Because cyanotoxins are not always visible, the city urges residents to exercise caution.
Health and Safety Risks
Blue-green algae, scientifically known as cyanobacteria, occur naturally in Minnesota lakes and ponds. Under warm and nutrient-rich conditions, they can multiply into harmful algal blooms (HABs) that sometimes produce toxins capable of causing illness in people and animals.
“It’s important to remember that you can’t tell if a bloom is toxic just by looking at it,” city officials said in a statement. “When in doubt, stay out.”
Exposure to toxic blooms can lead to symptoms such as skin irritation, nausea, headaches, or, in severe cases, more serious health impacts. Pets and children are especially vulnerable.
Advisory in Effect at Crooked Lake
Warning signs have been posted at Crooked Lake Park to alert visitors. Residents and parkgoers are advised to:
Avoid contact with water that appears discolored, scummy, or paint-like.
Keep pets and children away from water with visible algae.
Rinse thoroughly with fresh water if contact occurs.
City officials stress that toxins can remain in the water even after visible blooms have dissipated.
Staying Informed
The City of Coon Rapids is working with the Coon Creek Watershed District and the MPCA to monitor conditions at Crooked Lake. Residents are encouraged to check official city updates and consult MPCA resources for more information on harmful algal blooms and public health guidance.
For more on harmful algae and safety recommendations, visit the Minnesota Pollution Control Agency’s Blue-Green Algae webpage.
Overcast , with a high of 82 and low of 68 degrees. Overcast for the morning, sunny for the afternoon and evening, thundery outbreaks in nearby overnight.
70° and Thundery outbreaks in nearby
