HEALDSBURG, Calif. - Warnings are back up, for the first time this summer, about toxic algae in the Russian River.
Three of ten beaches tested showed the presence of naturally-occurring toxins produced by blue-green algae.
Those beaches are Cloverdale River Park, Patterson Point west of Guerneville, and Del Rio Woods Beach in Healdsburg.
All three will remain open, and swimming is allowed, but signs at all ten beaches advise caution for small children and dogs, who are especially susceptible.
"We were only at the river for a couple of hours before Posie passed," recalled Brooke Rudas of San Jose, still emotional about the death of her two year old golden retriever who died on a float trip on the Russian River in August of 2015.
"I didn't see her drink any of the water. She was jumping in and out of the boat, and swimming beside us," explained Rudas, who had no idea Posie had ingested the algae, which mixes with other river scum, but produces a lethal toxin.
Warmer water is more susceptible and across California, lakes and rivers are experiencing toxic algae bloom.
"We now test the beaches that are the most popular and frequently-used," Sonoma County Health Officer Dr. Karen Milman told KTVU.
The weekly testing began July 17, and the following Monday, trace levels were discovered.
Caution is the lowest level of alert.
"When we get up to the warning level, that's when we say people shouldn't be swimming in the water," explained Milman, "and at the danger level, the beach would be closed."
At Del Rio Beach, the shoreline is dotted with prominent signs warning of the danger.
"We want people to know there's the potential that toxins are in the water so take precautions, protect themselves and their animals but other than that, go and enjoy the river," advised Milman.
Some who live on Fitch Mountain, near Del Rio beach, wonder if the threat is well understood.
"The weekend will be the test, the proof," resident Betsy Sliney told KTVU, as she walked her two dogs Thursday evening.
"I'm aware of the algae, but I don't know if everybody is. And some people figure they've always swam in the river, and so have their dogs, and they're not going to change anything."
For her part, Brooke Rudas wishes the awareness and warnings had been more prominent when she and her husband took Posie on the canoe that fateful day.
It was an excursion they'd enjoyed several times before without problems.
"It's not worth the risk to go in the water, if you don't need to," Rudas declared, "so just wait for the water levels to rise, wait for warnings to go away."
Her beloved pet started the day healthy, then began convulsing and died in the canoe.
"She was shaking, and she seemed cold, So I held her, because she's my baby and I loved her," said Rudas, weeping,"and I still think about her every day."