Sedona, Arizona — The water in Sedona rose to 11 feet (3 meters) in less than 24 hours, prompting the evacuation of hundreds of residents from their homes, authorities said Monday.

The river, which flows through the town of Sedona and empties into the Arizona-Mexico border, rose to more than 11 feet in just under 24 hours.

The river’s height and the number of people living in the town, some of whom had to be evacuated, were also raised as a precautionary measure, according to the Sedona Fire Department.

Sedona Mayor Steve Miller said in a statement Monday night that residents of the city of 6,000 should stay at home until the river recedes, after which they will be allowed to return to their homes.

Miller said the river could crest again Monday night, possibly even higher than the high water mark seen in a flood of about 25 feet in the early 1980s.

The flooding is the worst in Sedano in years.

It has left homes submerged and at least 20 people dead.

Suspiciously, the floodwaters reached the Sedano Community College campus, a large building on campus, Miller said.

“We are taking measures to protect our campus.

We’re going to continue to make every effort to protect the campus and the people living there,” Miller said Monday night.

The city’s Emergency Operations Center tweeted Monday night about a high-water watch for Sedona.

Authorities have closed the river’s upper reaches, including parts of the town where the water has been rising.

The National Weather Service in Tucson also issued a high flood warning for the state of Arizona, the Navajo Nation, the U.S. Fish and Wildlife Service and the Bureau of Reclamation.

The National Weather System Center in Denver issued a flood watch for portions of Arizona.

In Sedona on Monday, water reached the city’s water tower.

People were advised to stay indoors.

Authorities in the community of about 2,200 people reported flooding, and residents in Sedonas town hall were told to stay at their homes for safety.

The town was placed under mandatory evacuation orders, and a high tide advisory was issued.