The forces of fire and ice shaped Yellowstone National Park over thousands of years. It took decades longer for humans to tame it enough for tourists to visit, often from the comfort of their cars.

In just days, heavy rain and rapid snowmelt caused a dramatic flood that may forever alter the human footprint on the park’s terrain and the communities that have grown around it.

The park is closed to visitors for the first time in 34 years.

The historic floodwaters that raged through Yellowstone this week, tearing out bridges and pouring into nearby homes, pushed a popular fishing river off course — possibly permanently — and may force roadways nearly torn away by torrents of water to be rebuilt in new places.

“The landscape literally and figuratively has changed dramatically in the last 36 hours,” said Bill Berg, a commissioner in nearby Park County. “A little bit ironic that this spectacular landscape was created by violent geologic and hydrologic events, and it’s just not very handy when it happens while we’re all here settled on it.”

The unprecedented flooding drove more than 10,000 visitors out of the nation’s oldest national park and damaged hundreds of homes in nearby communities, though remarkably no was reported hurt or killed. The only visitors left in the huge park straddling three states were a dozen campers still making their way out of the backcountry.

The park could remain closed as long as a week, and northern entrances may not reopen this summer, Superintendent Cam Sholly said.

“I’ve heard this is a 1,000-year event, whatever that means these days. They seem to be happening more and more frequently,” he said.

Sholly noted some weather forecasts include the possibility of additional flooding this weekend.

The northern part of the park is “likely to remain closed for substantial length of time due to severely damaged, impacted infrastructure”, the park said in a Tweet Tuesday.

The park’s website said visitors planning on traveling to the park in the coming weeks and month should check for updates.

Days of rain and rapid snowmelt wrought havoc across parts of southern Montana and northern Wyoming, where they washed away cabins, swamped small towns and knocked out power. This hit the park as a summer tourist season that draws millions of visitors was ramping up during its 150th anniversary year.

Some of the worst damage happened in the northern part of the park and Yellowstone’s gateway communities in southern Montana. National Park Service photos of northern Yellowstone showed a mudslide, washed-out bridges, and roads undercut by churning floodwaters of the Gardner and Lamar rivers.

In Red Lodge, a town of 2,100 that is a popular jumping-off point for a scenic route into the Yellowstone high country, a creek running through town jumped its banks and swamped the main thoroughfare, leaving trout swimming in the street a day later under sunny skies.

Residents described a harrowing scene where the water went from a trickle to a torrent in just a few hours.

At least 200 homes were flooded in Red Lodge and the town of Fromberg.