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About Algae Season

As temperatures heat up during spring and summer, be on the watch for algae blooms when recreating in Oregon lakes, rivers and reservoirs.

When an algae bloom is detected and lab results show that cyanobacteria or their toxins are present, OHA issues a health advisory warning people to stay out of affected water to avoid illness.

We send health advisories via the media, email, and we post this information here on the HABS website. Sign up to receive email alerts.


Exposure to cyanobacteria can be serious and result in a range of symptoms including skin rash, diarrhea, cramps, vomiting, numbness, dizziness and fainting. Children, people with weakened immune systems and pets are most vulnerable to illness.

Pets are at risk, too

Over the past three years, we’ve had reports of dog deaths due to exposure to bloom-affected water. HABS and Douglas County Health Department conducted specific outreach efforts along the South Umpqua River and mainstem Umpqua River following widespread publicity of dog deaths in the area, and the effort will continue this year. 

When to avoid water contact

Because only a fraction of Oregon’s fresh waters are monitored, the public can’t count on being notified about all harmful algae blooms, so there are certain conditions you can identify to stay safe and healthy. If the water smells bad or looks foamy, scummy, thick like paint and pea-green, blue-green or brownish-red in color, it’s best to stay out.

The HABS program is funded through a federal grant from the U.S. Centers for Disease Control and Prevention. The program relies on local, state and federal agencies that manage water bodies to alert it when a potentially toxic bloom has been detected. Information about harmful algae blooms and the HABS program are updated as this data and other information become available to us.

Be safe,

Curtis Cude
Program Manager
Oregon EPHT & Healthy Waters Programs
Public Health Division
Oregon Health Authority