It's anybody's guess what'll happen on Mount Tabor this weekend.

Organizers protesting the city's decision to drain the landmark's open-air reservoirs aren't ruling out serious confrontation. The city's parks department sent out a release this morning saying it anticipates a "peaceful, unpermitted demonstration."

For now, all that's certain is Mount Tabor Park's sort of locked down and that an untold number of demonstrators—calling themselves Camp Cascadia—are planning to ascend the old volcano in hopes of forcing the city to reverse its position. The park's closure at midnight tonight will be the true test of the movement's strength.

It's got some momentum. Many of these same (expected) demonstrators, remember, are coming in to this issue fresh from a decisive victory in Portland's fluoride vote a couple months back. These are people who've championed the purity of Portland's water, and see underground reservoirs planned for Powell and Kelly buttes as potentially harmful. Kim Kaminski, a leader in the fight against fluoride, is expected to participate in this evening's protest.

Park rangers for weeks have been fretting over how to handle the demonstration, and the city's release this morning called on protestors to respect the various activities—including weddings—the park hosts on summer weekends. Meanwhile, police have said they're not planning any heavy-handed tactics.

The city since 2006 had fought a federal mandate to cover or drain the city's open-air reservoirs—both on Tabor and across the city in Washington Park. City council—notably without the support of Commissioner Amanda Fritz, who's in charge of parks—announced last month it was "faced with no other legal options," and would stop fighting the feds. There's a now a late 2015 deadline to have the Tabor reservoirs drained.

Anyway, I'll be out there this evening, tweeting at @dirquez, if you're interested in the scene but don't feel like climbing a big hill.