Local, state and federal agencies are preparing for the worst this August, as peak fire season coincides with one of the biggest tourism events Oregon has ever seen.

The 2017 total solar eclipse - an event that won't return to Oregon until 2169 - is coming on Aug. 21, typically a dangerous time for wildfires. With an estimated 1 million people traveling to the 60-mile-wide path of totality, there's a very good chance for a spark, a blaze and a large-scale disaster.

Officials have spent all year planning, running simulations and coming up with worst-case scenarios, honing inter-agency communication to prepare as best they can. Chief among their concerns are campers that either don't know about fire dangers, or don't care about the rules.

On top of that is a fire danger that's especially high this summer: tall, dry grasses ignited by cars parked at campgrounds, parks or pulled over on the side of the road.

In central Oregon - where eclipse viewing is prime, and fire dangers are high - an estimated 400,000 people may show up, most from out of state, and likely some with little or no experience in the outdoors. Of course, with an event as unprecedented as this year's eclipse, there's just no telling who will show up.

"All of those things are so unknown that we're planning for the worst, but we really don't know what it's going to look like," Alex Robertson, an officer with the Central Oregon Fire Management Service, said. "All it takes is less than a percent of those people to do something stupid."

Robertson said he's taken part in simulations with local, state and federal agencies around Oregon, all hammering out plans for preparation and improving lines of communication. It's something they've been working on to get ready for the Cascadia Subduction Zone earthquake, he said, but the eclipse will be a sort of practice run to see how the agencies work together.

What's emerged from those simulations is a tricky kind of balancing act when it comes to fighting fires during the eclipse: They'll need to position crews and trucks ahead of time in places where they'll be able to get to fires, without getting stuck in the inevitable traffic jams that could snarl main arteries and back roads alike.

If a fire does break out, the primary issues will be how crews can best access it and whether any people need to be evacuated. It's the latter scenario that could take things from bad to worse.

"There's going to be ad hoc communities in the middle of the forest," groups gathered just for the eclipse, Robertson said, in addition to the small towns around them. "Our worst case is we are no longer trying to put out fires, we're trying to get people away from them."

With so much unpredictability, the primary line of defense will be communication. Officials are planning on alerting travelers to any campfire bans via electronic signs on the highway, and in some cases, driving around to campgrounds to check in on people.

A lot of the campgrounds are primitive, and lack some common amenities - including water. Oregonians who know the area, or who are used to backcountry camping, will know to bring plenty of supplies, but out-of-state travelers may not. That means it may fall upon locals' shoulders to help educate and police others, especially when it comes to fire danger.

Robertson said aside from common fire dangers - like unattended campfires, stoves and cigarettes - this year will be especially dangerous for fires ignited by cars. Tall, dry grasses can easily be ignited by a hot undercarriage or a tailpipe, he said, not just at campgrounds but on the side of the road.

The potential for fire danger is extremely high this August, but how bad things get will depend on all those unknown factors: how many people will show up, where they go, how responsibly they act and what fires will are already burning in the path of totality.

Regardless, the combination of the eclipse and fire season this year has been a good opportunity to bring Oregon's separate agencies together. Future incidents could benefit from a strong foundation built this summer.

"I think in a lot of ways it's opened the doors for some new relationships," said Traci Weaver, a fire communications specialist for the U.S. Forest Service and Bureau of Land Management. "[We're] just trying to make sure that everybody is looking at this holistically."

They're also crossing their fingers that all those worst-case scenarios don't come to life this August.

--Jamie Hale | jhale@oregonian.com | @HaleJamesB