PORTLAND — After months of hype, it's almost here.
The first coast-to-coast total solar eclipse in the United States since 1918 is expected to draw up to a million people to Oregon — where the moon's shadow will first make landfall — and crowds have already begun clogging roadways, campgrounds and hotels for hundreds of miles.
A growing wildfire in the central part of the state Friday complicated plans, and authorities ordered mandatory evacuations for about 1,500 people just as thousands more were expected to start arriving. Officials were closely watching another blaze near a Native American reservation.
Traffic in central Oregon started picking up Wednesday as 30,000 people poured in for a large festival near the town of Prineville, creating miles-long backups on U.S. 26. Across the Northwest, planners are bracing for more of the same this weekend and into Monday as more tourists arrive.
In neighboring Idaho, up to 400,000 people could show up. Major traffic jams also are expected in Washington state as people try to drive south or east to prime viewing locations.
Officials have also been grappling with the possibility that cloudy weather, closed roads or coastal fog could prompt eclipse-watchers to change plans at the last minute, throwing traffic into chaos.
"It's tough to say which one is the biggest wild card: traffic, wildfires or weather," said Cory Grogan, spokesman for the Oregon Office of Emergency Management.
"What we do know is that this is unprecedented, with all our campsites and hotels full and all these people coming in for special private events. It's going to be probably the most people we've ever seen in Oregon."
More than two dozen other wildfires are burning around Oregon, and nearly a dozen of them are in the path of totality, where the moon will completely black out the sun.
One of the most troublesome blazes has forced officials to shut down 183 square miles of trails, campgrounds and roads in and around the Mount Jefferson Wilderness Area — a prime eclipse-viewing spot.
Hundreds of people who intended to camp there or hike up Mount Jefferson to catch a stunning view of totality have had to change their plans.
A large portion of the Three Sisters Wilderness area is also closed because of the same fire that caused evacuations around the town of Sisters. Campfires are banned on all forestland and at coastal beaches because of high fire danger. Officials are also concerned about an unusually high tide overnight Monday that could surprise eclipse enthusiasts who camp out on Oregon's beaches.
The weather is another unknown, although predictions have firmed up considerably.
The forecast looks clear for Monday in Salem and central and eastern Oregon. But the coast — where the moon's shadow first makes landfall — may experience morning fog or early clouds.
That could send sky-gazers scrambling for a new viewing spot and further complicate an already difficult traffic mess, said Dave Thompson, a spokesman for the Oregon Department of Transportation.
Forty percent of Oregon-bound eclipse watchers are expected to be in place by Monday, but a recent Transportation Department survey reveals cause for concern.
About 11 percent of people headed to the central Oregon town of Madras, considered one of the nation's best viewing spots, are still planning to arrive Monday morning. That number is much too high, Thompson said, adding it could take six hours or more to travel the roughly 50 miles from Portland to Salem on Sunday.
"We don't want people to treat this as a game-day event. We're quite concerned if people think they can pop in Monday to watch the eclipse, then it's too late," he said.
In Idaho, the path of totality will cross from the western town of Weiser to the community of Driggs on the eastern side of the state. Idaho officials there are warning travelers to keep gas tanks full and pack extra food and water in their vehicles. Local government officials have also been stocking up on rattlesnake venom.
Some experts have estimated Idaho could see as many as 370,000 visitors for the eclipse. Weiser is expecting 20,000-plus visitors — a huge influx for a place that normally has just 5,500 residents.
To help the public, Oregon officials have activated a 211 phone number for updated information on traffic, weather and wildfires.
People hitting the roads can also check the state Transportation Department's TripCheck website for the latest on traffic. Oregon's Office of Emergency Management will be tweeting regular updates at @OregonOEM.