Heading into the final weekend of the summer recreation season, Jackson County has so far sidestepped an outbreak of toxic blue-green algae in any of its lakes this summer.

Heading into the final weekend of the summer recreation season, Jackson County has so far sidestepped an outbreak of toxic blue-green algae in any of its lakes this summer.

But that doesn't mean waterskiers and swimmers are out of the pea-green soup just yet.

Environmental factors still remain in place that could trigger an explosion of anabeana flos-aque and the requisite advisories against contact with reservoir water tainted by the green goo that is a regular summer visitor here.

"As the temperatures cool and the days get shorter, there is less potential now for a bloom — theoretically," said Gary Stevens, Jackson County's environmental health coordinator. "We just have our fingers crossed that we won't have any more activity."

In past years, county and state Department of Human Services officials have issued public-health advisories against water contact at Lost Creek Lake in the fall, well after Labor Day's end of the official boating season.

That keeps reservoir managers vigilant, spying for the tell-tale green slicks that denote massive algae blooms, which release toxins when they die off.

"We test visually all the time and if we see something beginning to brew, then we sample the water," said Jim Buck, the U.S. Army Corps of Engineers' project manager for Lost Creek and Applegate reservoirs.

While Applegate's cold and deep waters have been free of any known blue-green algae outbreaks, Lost Creek has seen two separate outbreaks each of the past two years.

Buck said occasional cooler weather and higher-than-normal flows into the reservoir this year may have helped the lake sidestep algae levels above World Health Organization thresholds that trigger warnings against contact for people or pets.

But the rhymes and reasons for algae blooms remain murky enough that all bets are off when it comes to predictions beyond the immediate future.

"We seem to be out of the woods for Labor Day weekend, but we're not out of the woods completely," Buck says. "This is odd stuff."

That's the same approach Umpqua National Forest officials are using at Diamond and Lemolo Lakes, forest spokeswoman Cheryl Caplan says.

Lemolo is the latest lake to come off a public-health advisory, which was lifted there late Tuesday — just in time for the final wave of campers taking advantage of the last long weekend before the start of school.

Since July 10, state, county and Forest Service officials have recommended that visitors avoid water contact and practice catch-and-release fishing until the advisory is lifted. The restrictions were not mandatory.

Swallowing or inhaling water droplets — as well as skin contact with water by humans or animals — should be avoided during the advisory periods. The toxins cannot be removed by boiling, filtering or treating water.

This algae strain, which is actually a form of bacteria, releases neurotoxins that can cause problems ranging from a skin rash and dizziness to rapid death, though documented reactions are extremely rare in Oregon.

It is most threatening to children and pets, and it congregates most in shallow, stagnant coves and along shorelines.

Lemolo was one of eight water bodies in Oregon to require a health advisory from algae this summer. Of those, only Odell Lake in Klamath County, Dorena Reservoir in Lane County and Devil's Lake in Lincoln County are still under advisories.

Reach reporter Mark Freeman at 776-4470, or e-mail mfreeman@mailtribune.com.