The Minneapolis Parks and Recreation Board says there is a hazardous algae warning at all three beaches at Cedar Lake. It’s the highest risk warning for blue-green algae. Conditions are currently ideal for blue-green algae, which include sunny skies and temperatures higher than 75 degrees. Neither people nor pets should make contact with water or ingest water with blue-green algae. Blue-green algae can look like pea soup or spilled paint floating on the surface of the water.