Every year at this time, tens of thousands of visitors flood the trails and scenic byways of Yosemite National Park in search of one last summer communion with Mother Nature.

But now, as the devastating Rim fire rages through the High Sierra and spreads deeper into Yosemite, would-be park visitors are having to decide whether to cancel plans made months or years in advance or press ahead with a visit that could potentially end in a smoky evacuation.

Many are choosing to keep their date with El Capitan and Half Dome.

“Do you know how hard it is to get reservations up here? We’ve been trying for two years,” said Mona Carrizosa, 44, of Corona. The middle school instructional aide and her boyfriend, Jose Gutierrez, 31, said they weren’t about to pass on the opportunity. In fact, they said they were delighted to find the park less crowded than anticipated.

“I know it’s bad for business, but for visitors it’s good,” Carrizosa said. “We’ve never seen it like this.”

Park officials say traffic is lighter than it usually is heading into Labor Day weekend, but that campsites remain full and lodges are still receiving guests.

“We are definitely encouraging visitors to not cancel their plans,” said Kari Cobb, a park ranger and spokeswoman. “They might have to modify their plans, meaning they’re going to have to come in through a different entrance, but the park is a very, very big place.”

The wildfire has scorched roughly 5% of the park, but is still some 20 miles from the attraction’s most popular area, the granite-walled Yosemite Valley. And though a massive plume of smoke has been observed by astronauts in the International Space Station, there has been no hint of smoke in the valley.

Other areas of the park have been affected, however.

Officials closed the campground and lodge at White Wolf and barred access to the popular Hetch Hetchy Reservoir. More of Tioga Road, or California 120, has been closed, effectively cutting off the east-west route through the park. As a result, Yosemite Valley is accessible only from the west, via California 41 and 140. Tuolumne Meadows is now accessible only from the east, via Highway 120 near Lee Vining.

On Wednesday morning, Alan and Garcia Williamson crammed several days of sightseeing into just a few hours so they could avoid the noon Tioga Road closure and make it to Mammoth Lakes on the eastern side of the Sierra.

The husband and wife had traveled from Scotland to see Yosemite as part of a month-long vacation in the United States and Canada and never considered canceling their plans, they said.

“We just did our research and found out where the fire was,” Garcia said. Though their hotel told them it had been fielding cancellation calls all day, “It’s not as bad as people think,” she added. “So we’re going to press on.”

Friends and relatives back home have sent text messages asking the Williamsons if they are in danger. “They think the whole park is ablaze,” Alan Williamson said.

Yosemite’s busiest month is usually August, when it frequently draws more than 600,000 visitors, according to the National Park Service. Of the roughly 4 million people who visit each year, one quarter are from overseas — Germany and the United Kingdom in particular. More than 60% are from California, however, and the average cash expenditure for each visitor is $242, according to the park service.

Steve Hollenhorst, a park management and natural resource expert at Western Washington University who has studied national park visitors and their perceptions, said the decision to abandon a family trip was not an easy one.

“These types of experiences are really important to folks, so they find ways to adapt and make it work,” Hollenhorst said. “People plan to visit months and years in advance. Once those plans are firmed up, they’re loath to change them.”

While news footage of the fire and plumes of smoke might keep some visitors away, Hollenhorst predicted a surge in visits once the fire has run its course.

“People want to see nature in action,” he said. “When the fire’s gone they’ll want to come and see what it looks like.”

Such was the case after portions of Yellowstone National Park burned in 1988, Hollenhorst said: “People became very interested in the ecology of fire, and that became part of the story of the park.”

Of course, Yosemite is already a monument to the awesome violence of nature. Its picturesque granite domes and inviting valley are remnants of molten rock that was pushed and angled toward the heavens, then carved and polished by powerful glaciers and erosive water.

Wednesday was a peaceful summer day on the valley floor. As temperatures climbed into the 90s, visitors rode bicycles, set up picnics and lazed along the banks of the gently flowing Merced River, beneath bright blue skies.

In one area, a crowd of visitors gathered around a pair of telescopes that were trained on two distant climbers scaling the sheer granite face of El Capitan. In the bright sun they looked like ants against the monolith.

Among those who gathered for a peek was Daniel Posner, a New York City resident who was visiting for the first time with his wife and six children.

“For us, this is a once-in-a-lifetime experience and we came out here just to see it,” Posner said.

Posner said he worried at first that smoke would sour their visit, but now the family is making plans to visit Glacier Point, where they were told that they might catch a glimpse of the fire’s massive plume.

“I think it will be a cool experience for my kids to actually see what a forest fire looks like,” Posner said.

Barboza reported from Yosemite National Park, Morin from Los Angeles.

(c)2013 the Los Angeles Times. Distributed by MCT Information Services.

Photo Credit: Tourists enjoy the view at Glacier Point in California's Yosemite National Park on August 27, 2013, as the Rim fire continues to rage about 25 miles away. Barbara Davidson / Los Angeles Times/MCT