FOLSOM LAKE -- No amount of warnings were going to keep people away from Folsom Lake on the last holiday weekend of the summer.
But state parks officials posted warnings for harmful algae at the lifeguard stations near the beach. They warned people to stay away from scum and discolored water, because across from the Beal's Point beach in an area called Mooney Ridge a dog fell ill with symptoms of ingesting toxins caused by algae blooms.
Symptoms for dogs include vomiting, diarrhea, foaming at the mouth and muscle twitching. Children can also become victims of skin, eye and throat irritations or difficulty breathing.
Many were oblivious to the warnings, swimming in calmer waters where algae blooms can run wild.
Others, especially dog owners, were more aware.
"If there's anything that endangers my dogs, I probably won’t let them in the water," visitor Nico Soto said.
The same goes for his two daughters, he said.
Soto was on the lookout for anything suspicious in the water like a thick paint-like film on the surface. It’s not always blue-green, too. It can be white, red or brown as well.
"It's kind of self-explanatory. If you see something that’s not supposed to be there in the water, you kind of … it makes you think," Soto said.
The problem is the variety of bacteria producing algae.
Warnings were also posted at Oregon Bar on the North Fork of the American River in the Auburn State Recreation Area, a popular hiking area for dog owners to take their dogs.
One dog died here a couple of weeks ago after playing in the water.
State Water Board testers found harmful cyanobacterial mats growing on rocks beneath the surface in wadeable water.
Other harmful algae can grow at medium depths below the surface and scum can exist onshore for a time.
Because algae blooms can come and go so quickly, it's hard to predict which areas will be dangerous and for how long.
Algae blooms are not new this time of year, but state officials say we can expect more of them because of climate change.