Warmer than normal fall weather contributes to algae blooms at several Minneapolis lakes
Posted on 30 September, 2021September’s warmer weather has contributed to blue-green algae blooms at several Minneapolis lakes. Currently, Lake Hiawatha and Lake Nokomis are both experiencing algae blooms, with other lakes having the right conditions for potential blue-green algae blooms.
Blue-green algae blooms are harmful when they produce toxins that can make humans and animals sick. Most blooms are not harmful, but you can’t tell by looking at it if a bloom is harmful or not. It is recommended that people and pets stay out of the water when these blooms or algae scum are visible. Water conditions change quickly and scum is moved easily by wind, so it is not possible to post all locations where blooms occur.
Fall algae blooms are unusual but are becoming more common as the region becomes seasonally warmer on average. This is not a Minneapolis-only phenomenon. Other lakes in the metro and region are having the same issue.
To reduce your exposure or your pet’s exposure to blue-green algae:
- Avoid or minimize recreating or making body contact in waters that appear to have a blue-green algae bloom; if you do come in contact with algae-laden water or scum, wash with fresh water afterwards.
- Don’t let animals swim or drink where there is noticeable algae in the water or scum on the shore.
* Note: Dogs are not allowed in Minneapolis water bodies, per MPRB ordinances.
The Minneapolis Park Board staff monitor the lakes throughout the year and continue to update the online beach map, which includes blue-green algae information.
Please see the Minnesota Pollution Control Agency (PCA) webpage on harmful algal blooms for additional information on blue-green algae.
Fact Sheets from Minnesota’s PCA and Department of Health
Harmful Algal Blooms (HABs) – English (PDF)
Harmful Algal Blooms (HABs) Hmoob (PDF)