A harmful algal bloom is once again showing up on the Snake River. This is the fourth year in a row that Whitman County Public Health leaders have warned about algal blooms in the river.
The bloom is showing up intermittently along 50 river miles in the stretch of river between Blyton Landing and Little Goose Dam. That’s slightly farther upriver than in years past.
Water samples tested positive on Aug. 18 for microcystin, a liver toxin. Health leaders say people, pets and livestock should avoid any part of the river that looks like it has green or blue scum. It can look similar to spilled paint.
It can look similar to spilled paint and can also be brown, red or pink. The bloom could move downstream with the river current.
Don’t drink, swim or get in the water if you see a bloom. Wash any algae or discolored, smelly water off your skin and clothing. Boiling water won’t get rid of the toxins.
Before 2023, toxic algae hadn’t been detected in the Snake River. At that time, health leaders said they hoped harmful algal blooms wouldn’t become a yearly occurrence on the Snake.
“Usually rivers aren’t this bad, but we also have the dams. These blooms like stagnant, warm water with high nutrient load,” said Maddy Lucas, an environmental health specialist with Whitman County Public Health, in an earlier interview.
Health leaders have monitored the river since. Various algal blooms have been detected around the state this summer, including Howard Amon Park in Richland.
“It’s incredibly difficult to pinpoint the origin of a toxic algae bloom, especially in a river system,” Lucas wrote in an email.
The algae is made up of a bacteria that exists naturally in the river. But when a variety of conditions trigger it to grow rapidly — like warmer weather, fertilizer runoff or sewage leaks — it forms blooms. Those blooms produce the toxins.
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