The river reached its peak overnight, nearly 3 feet higher than during flooding the previous year, La Roux said. The crest was the second highest on record and the highest since 1911. County officials were still assessing the damage Friday as water levels began to recede; La Roux said they expected the river to start dropping around 6 p.m.

Search-and-rescue crews were working to reach people stranded by floodwaters and damaged roads. Around 2:30 a.m., an occupied recreational vehicle was swept about 100 yards downstream and left stranded in the river. Two adults and two dogs were inside, La Roux said, and responders were waiting for a Colorado National Guard helicopter to assist with a rescue.

Earlier Friday, a swift-water team rescued an elderly couple who had become stranded across a flooded road. The couple were hypothermic, La Roux said.

County Manager Longinos Gonzalez Jr. said some residents were unable to travel between areas because roads had been closed or damaged, though those people were safe in their neighborhoods. Officials were awaiting additional air resources to help with potential rescues.

Mandatory evacuations had been ordered late Thursday for low-lying and flood-prone areas along four rivers in southwest Colorado. Gov. Jared Polis declared a disaster emergency covering Archuleta and 10 other counties: La Plata, Montezuma, Dolores, Hinsdale, San Miguel, Ouray, San Juan, Mineral, Alamosa and Rio Grande.

The declaration activates the state emergency operations plan and authorizes National Guard air, ground and engineering support for flood response, evacuations and search-and-rescue operations.