"If we get that window of opportunity, which it sounds like we might get, we have the horsepower to hit it hard," federal incident commander Shane Del Grosso said.
Authorities Sunday issued instructions to stranded residents via news and social media how to flag down one of those helicopters.
"Wave a sheet, put a sheet on the roof, fire off flares, even use a small fire so we can see the smoke," said Ben Pennymon, spokesman for the Boulder County Office of Emergency Management.
He also recommended using a mirror to reflect sunlight.
"And we're asking people to be ready to go," Pennymon said.
Medicine, clothes any other critical items should be in "go bag," he said.
Off the field, into the kitchen
The University of Colorado's football players, whose home game against Fresno State was canceled Saturday, instead served lunch to about 800 evacuees.
The food had been delivered to the stadium for the canceled game, and university officials didn't want it to go to waste.
Many of the recipients had been displaced from student housing, the university's athletic department website reported.
"Tragedies like this can make you feel really separated from the rest of the world," said Sarah Stith, a resident manager of a school apartment complex. "And it's things like this that just make you realize what a great community we have."
Students from several school athletic teams dished out food, cleaned tables and entertained children by signing autographs and taking photos.
Wide receiver D.D Goodson said the water was waist-high in his own room.
"I lost my sofa, my television and some of my shoes and other necessities. It's nice to help these evacuees because I know what they are going through," Goodson said.
In Evergreen, about 15 miles west of Denver, many of the 9,000 residents are so eager to help that the fire department had to issue a "Thanks, but no thanks."
First, the Evergreen Fire Rescue Department tweeted, "Thank you for donations of food but please no more. If you want to help, go to (Station) 2 for sandbagging tonight."
Forty minutes later, came another tweet: "Thank you Evergreen neighbors! EFR has plenty of help sandbagging."
No government gridlock here
Sen. Mark Udall was on a helicopter reconnaissance mission with Hickenlooper and other elected officials Saturday that twice was diverted to pick up groups of stranded residents.
"That dog and the cat and those seven people on those two helicopters didn't ask us whether we were Democrats or Republicans," Udall said.
He promised a bipartisan push in Congress for federal aid for flood recovery.
Hickenlooper got a call Sunday from President Barack Obama, and FEMA Administrator Craig Fugate will arrive Monday. A joint National Guard-U.S. army command and hundreds of FEMA workers are already in the state.
Boulder County alone will need an estimated $150 million to repair 100 to 150 miles of roadway and 20 to 30 bridges, county transportation director George Gerstle said.