Unprecedented and sudden flooding at the oldest national park in the US this week has caused widespread damage to its roads and infrastructure and surrounding communities.
Some 10,000 visitors were evacuated on Monday from Yellowstone National Park, a blow to the 150-year-old park at the height of its tourist season.
It's the first time the park, which spans parts of the US states of Wyoming, Montana and Idaho, has closed in 34 years.
As the raging waters spread to low-lying areas along the river, flooding is expected in Billings - the state's largest city - and to eastern parts of Montana.
The floodwaters have overtaken roads and bridges, triggered power outages, and caused mud and rock slides.
Several homes have been lost, with at least one house washed into the river.
A combination of heavy weekend rains and snowmelt had pushed the Yellowstone, Stillwater and Clarks Fork rivers to record levels by Monday, the National Weather Service said.
The Yellowstone River runs through the states of Wyoming and Montana.
No deaths or injuries have been reported related to the weather event, but about 10 rescues have been made so far by boat and air, according to the county government.
Typically, the park attracts more than four million guests each year, a boon to the local economies that rely on the tourism it brings.
That annual tourism wave usually ramps up in June and does not abate until the fall - but officials say at least the northern half of the park is likely to remain closed all summer.