Flood damage to one section of Yellowstone's Northeast Entrance road/NPS

Washed away roads, damaged water and sewer systems, and other unknown infrastructure and trail damage from what might have been a "once-in-a-thousand-year-storm" greatly complicates how soon Yellowstone National Park can reopen, and in what condition, and the odds are long that it will fully return to normal this year, Superintendent Cam Sholly told a national audience of journalists Tuesday during an hour-long Zoom call.

And while the flooding from heavy rains Sunday night into Monday, and the snowmelt that precipitation generated, was subsiding Tuesday, the weather forecast raised the worrying possibility of more rain this coming weekend to compound the park's problems, he said.

"There are some conflicting predictions about this weekend and whether or not we may have another high-water event coming," said Sholly, pointing out that there remained another foot of snow in Yellowstone's high country yet to melt. "If we get warming temperatures and the right mixture of precipitation like we did Sunday, we could have another flood event coming to Yellowstone in the upcoming four or five days."

The news conference, which also involved Park County, Montana, Commissioner Bill Berg, came as the full extent of the storm that dumped 2-3 inches of rain on top of 5.5 inches of snow that quickly melted was still being measured. The five-mile-long road from Gardiner, Montana, through the park's North Entrance and down to Mammoth Hot Springs had been erased in multiple spots by the floodwaters and raised the question of whether it could, or even should, be rebuilt in the same riverside corridor.

The park road east of Mammoth Hot Springs and Tower through the Lamar Valley to Silvergate and Cooke City in Montana also had been washed away in several places. There existed the possibility that the sewer line that ran from Mammoth Hot Springs beneath the Gardner River to the town of Gardiner had been broken and was leaking raw sewage. Water and power lines around Mammoth also had been impacted. A house owned by the National Park Service in Gardiner that six park workers and their families called home was pulled into the raging waters and washed five miles downstream.

This was to be a celebratory year for Yellowstone, which is marking its 150th birthday, but the storm demonstrated once again that nature has always had the final say over life on this landscape.

"It's a little bit ironic that this spectacular landscape was created by violent geologic and hydrologic events, and it's just never handy when it happens while we're all here settled on it," said Berg.

Park Service employee housing in Gardiner, MT, got washed down the Gardner River/NPS

Monday dawned with the need to evacuate park visitors from the northern half of the park, that section north of Old Faithful, Canyon, and Madison, as daylight revealed through the rain showers the catastrophic, and extensive, damage.

"Once we got the visitors yesterday out of the northern loop, we proceeded to start evaluating more carefully what the impacts of flooding were on the southern loop. Everything from the roads to the bridges to wastewater treatment facilities and those types of things," Sholly said in describing the decision to close the park, a closure likely to run into next week. "The damage on the southern loop [of the park road system] is much less than the northern loop. However, there are several areas on that loop that are potentially compromised that we're evaluating."

The storm's arrival at the start to the busy summer travel season wasn't lost on Sholly, who didn't need to remind anyone that Yellowstone is a global destination for millions who want to see seething geysers, steaming hot springs, herds of bison and elk, wolf packs, and grizzlies. During the summer months the park can receive 1 million visitors a month, he pointed out.

But he also noted out that the northern half of the park would remain closed for the rest of summer because of the storm damage, and that it was impossible for "half the park ... to support all the visitation." As a result, Park Service officials are considered the possibility of using a timed-entry reservation system much like that being used at Rocky Mountain National Park in Colorado this year to control visitation.

But before any visitors return, crews need to conduct damage assessments.

"The million-dollar question is, what's the damage? The answer is we don't know exactly yet," said Sholly. "Water is extremely high. We're not putting teams in harm's way at this point. When the water subsides, probably early next week, we will be pulling together a large number of people from different agencies around the country to come to Yellowstone and help us assess what the damage is to various infrastructure in the park."

Rebuilding the North Entrance road between Gardiner, MT, and Mammoth Hot Springs in the park could require moving it away from the Gardner River and into a more resilient corridor/NPS

Putting a cost estimate on the damage and what it might take to repair is anyone's guess at this point, he said, later adding that he's not worried about finding the funds necessary to address the needs.

"I think this is a pretty important thing," said Sholly. "I've had good conversations with the Department of Interior Secretary Deb Holland, the director of the Park Service, Chuck Sams. I think that we have good support from Congress. We have a variety of different funding sources that we can look at. I can't promise everything's gonna come in exactly when we need it. It's incumbent upon us here in the park to make those assessments, put with those packages together, get the cost estimates, and then work with as many people as possible in as many fund sources as possible to get them funded as quickly as possible."

While the superintendent thought the southern half of the park, with access via the South Entrance near Jackson, Wyoming, the West Entrance at West Yellowstone, Montana, and the East Entrance near Cody, Wyoming, might reopen in the near future, he hesitated to put a date on it.

"Because the power has been out for as long as it has, we've had wastewater treatment facility failures in multiple locations, backup generator failures, reinforcing the decision to move visitors out of park as a good one. But all of that infrastructure is going to need to be checked and evaluated before we want to put visitors back in the park," the superintendent said.