Overview
- The Minneapolis Park and Recreation Board has placed Lake Nokomis Main Beach and 50th Street Beach under a hazardous algae advisory after seasonal samples showed microcystin levels above the Minnesota Pollution Control Agency safe‑swimming threshold.
- Officials said recent hot, sunny weather and water temperatures above 75°F create conditions that encourage blue‑green algae, a cyanobacteria that can produce the toxin microcystin.
- Health guidance warns people to avoid water that looks like pea soup or spilled paint, keep children and pets away from algae scum, throw away fish guts and rinse fillets before eating, and shower immediately after any exposure.
- Officials have not set a timeline for lifting the advisory and will use follow‑up sampling to confirm toxin levels are back below state limits before reopening the beaches.
- Blue‑green algae blooms are common in summer and this advisory highlights the need for ongoing weekly monitoring and public alerts to protect swimmers, pets, and local recreation plans.