Sunny skies greeted rescue crews Tuesday working to contain the secondary effects of last week's biblical flooding in Colorado, which has killed at least six people so far.
Authorities were focusing their efforts on the foothills of the Rocky Mountains, where prairie towns were being evacuated as the flood crest moved downstream. Downstream flooding swelled rivers farther east, and state officials ordered the evacuation Tuesday of the town of Crook.
The death toll climbed to six late Monday, the state emergency agency confirmed. It wasn't able to give out any more details, but The Denver Post cited police as saying an 83-year-old man was swept away in Idaho Springs.
Authorities initially said eight people had been killed, including two who were missing and presumed dead in Larimer County. Late Tuesday, they reclassified them as simply missing.
Almost half of the 1,200 people who were declared unaccounted for or missing Monday after the devastating floods have been found safe following an intensive search, according to figures released by the Colorado Office for Emergency Management.
More than half of those missing were in Larimer County, where two people were presumed dead, according to the local sheriff's office.
The flooding has affected 17 counties. It has killed eight people, damaged or destroyed 18,000 buildings and forced 11,750 people to evacuate their homes, acccording to the OEM.
Craig Fugate, head of the Federal Emergency Management Agency, traveled to Colorado on President Barack Obama's direction to meet with federal and state officials.
He joined more than 400 other FEMA personnel who were supporting response efforts on the ground.
Gov. John Hickenlooper said 21 helicopters were scouring the affected area to look for people trapped by the waters.
Kyle Fredin, a meteorologist for the National Weather Service, said 21 inches of rain fell in parts of Boulder, northwest of Denver, during the weeklong deluge, nearly double the area's average annual rainfall.
Saturday, Obama authorized federal aid to help state recovery efforts.
People in Boulder, Larimer, Adams and Weld counties are eligible for assistance with temporary housing, home repairs and low-cost loans to cover uninsured property loss, FEMA said.
Counties eligible for other types of assistance include Arapahoe, Broomfield, Clear Creek, Denver, El Paso, Fremont, Jefferson, Logan, Morgan, Pueblo and Washington.
Meanwhile, authorities warned residents to be on the lookout for rattlesnakes that might be slithering to higher ground.
Erin McClam of NBC News and Reuters contributed to this report.