Colorado emergency management officials revised the statewide death toll downward to six from eight.
"The two missing and presumed dead individuals from Larimer County are now listed under missing ... to more accurately reflect their status," officials said. Larimer County is around Fort Collins.
Clear skies Tuesday let National Guard helicopters and other emergency crews rescue residents and bring help to others, The Denver Post reported.
Rain was not forecast for the rest of the week except for isolated thunderstorms in the Rocky Mountains and foothills Wednesday afternoon and evening, the National Weather Service reported.
About 600 people still remained stranded in isolated areas of Larimer County, state officials said.
At the same time, some people refused to leave their homes, officials said.
This prompted rescuers to show them pictures of flood-damaged roads, letting them know the upcoming helicopter evacuation could be their last chance to leave for some time.
"Larimer County doesn't own any helicopters and won't be able to do any food and water drops," Larimer County Sheriff spokesman Nick Christensen told the Post.
"If they don't take this opportunity now, they may be there for a very long time," he said.
Major flooding was still reported along the South Platte River in the Colorado Plains as the river crest works its way downstream.
Runoff from last week's floods along the Rockies' Front Range rushed down the river into Nebraska, prompting the weather service to warn several Nebraska counties to be prepared as the river would overflow its banks Wednesday.
The river runs into Nebraska between Julesburg, Colo., and Big Springs, Neb. In Nebraska, it passes south of Ogallala and joins the North Platte River near the city of North Platte.