U.S. National Park Service: Yosemite National Park

Harmful algal blooms (HABs) are a growing concern for public health and the environment. These blooms, caused by the rapid growth of algae or cyanobacteria, can produce toxins that pose serious risks to humans and animals alike. Factors such as low water flow, intense sunlight, and high temperatures can create ideal conditions for HABs to thrive, with climate change potentially exacerbating these conditions in the future.

According to the Centers for Disease Control and Prevention (CDC), exposure to HABs can occur through various means, including skin contact during activities like swimming, inhalation of airborne toxins, ingestion of contaminated water, or consumption of tainted food or supplements. Symptoms of HAB-related illnesses can vary depending on the type of toxin involved, but may include stomach pain, headaches, vomiting, diarrhea, liver damage, and neurological issues such as muscle weakness or dizziness. Animals can also be affected by HABs, experiencing symptoms like excessive salivation, vomiting, fatigue, difficulty breathing, and even death.

In California, incidents of harmful algal blooms have been reported in locations such as Yosemite National Park. The HAB Incidents Reports Map provides a visual representation of these blooms, highlighting the need for monitoring and reporting of such events. Visitors are encouraged to report any large algae blooms they encounter, providing details on the location, date observed, and a general description of the bloom.

It is important to be aware of the potential dangers posed by harmful algal blooms and take precautions to avoid exposure. Avoid swimming or coming into contact with water that appears discolored or has a strong odor, as these may be signs of a bloom. Keep pets away from affected water sources and prevent them from ingesting algae or cyanobacteria. If you suspect exposure to HAB toxins, seek medical attention promptly to prevent further complications.

By staying informed and vigilant, we can help mitigate the risks associated with harmful algal blooms and protect both human health and the environment. Reporting any suspected blooms and following guidelines for safe water activities are crucial steps in addressing this growing issue. Together, we can work towards minimizing the impact of HABs and ensuring the well-being of all who enjoy our waterways.