Yellowstone officials said northern portions of the national park might remain closed for "a substantial length of time" due to severe flooding washing out bridges and roads.

"Many sections of road in these areas are completely gone and will require substantial time and effort to reconstruct," the park said in a news release. "The National Park Service will make every effort to repair these roads as soon as possible; however, it is probable that road sections in northern Yellowstone will not reopen this season due to the time required for repairs."

CNN reported that the unexpected flooding occurred Monday after the park and sections of Wyoming and Montana received historic rainfall and rapid snowmelt, which knocked out roads and bridges.

On Monday, officials announced the closure of all five park entrances to inbound traffic to wait for flood waters to recede.

Superintendent Cam Sholly added that 10,000 visitors had left the park since Monday.

According to the Associated Press, the park could remain closed for up to a week.

The news outlet reported that the northern entrances might not reopen this summer.

On Tuesday, Montana Gov. Greg Gianforte declared a statewide disaster.