Raging rivers in Yellowstone National Park washed out roads and bridges, knocked out power and left some people stranded Monday. Thousands of visitors were forced to evacuate parts of the nation’s first national park at the height of the summer tourist season.

Some of the worst damaged areas are in the northern part of Yellowstone and the park’s gateway communities in southern Montana.

Road access remains cut off to Gardiner, Montana, a town of about 900 people. Dozens of campers in Montana’s Stillwater County had to be rescued by raft.

No injuries have been reported yet, but the damage to homes and infrastructure is widespread and massive.

Melting snowpack coupled with several inches of fresh rain caused the flooding. Yellowstone got 2.5 inches of rain Saturday, Sunday and into Monday. The Beartooth Mountains northeast of Yellowstone got as much as 4 inches, according to the National Weather Service.

The Yellowstone River at Corwin Springs crested at 13.88 feet, which tops the previous record of 11.5 feet set in 1918.

The flooding happened while other parts of the country endure hot and dry weather. More than 100 million Americans were warned to stay indoors Monday as a heat wave settled over an area reaching from the Gulf Coast to the Great Lakes.

This is the first time Yellowstone National Park has closed in 34 years. It will remain closed until at least Wednesday.

The Associated Press contributed to this report.