LOS ANGELES (AFP) - The confirmed death toll from massive floods in the US state of Colorado has risen to seven, while hundreds more remain unaccounted for, officials said Monday.
Helicopters resumed search and rescue missions, helped by clearer weather after days of torrential rain that has left over 1,500 homes destroyed and more than 17,000 damaged.
Five teams from the Federal Emergency Management Agency (FEMA) are bolstering hundreds of state and local officers trying to reach hundreds of residents stranded by the floods, centered on Boulder County north of Denver.
On Sunday, torrential rain prevented helicopters from taking off for most of the day as officials put the number of people unaccounted for at more than 1,200 across the western state.
But on Monday there was even blue sky in places, allowing some 21 helicopters to take to the air.
"We are hoping to take advantage of the weather today and get those rescue operations complete," spokeswoman Micki Trost of the Colorado Division of Homeland Security and Emergency Management was quoted as saying by the Denver Post.
Three people are confirmed dead in Boulder County, but the state-wide death toll now stands at seven, Boulder Office of Emergency Management official Nick Grossman told AFP.
"Those are the numbers confirmed to us by FEMA," he said.
Rain began pelting the western state early last week, with Boulder especially hard hit, seeing 18.3cm of precipitation in about 15 hours starting on Wednesday night.
Flash floods have afflicted 15 counties down a 320km north-south section of the Front Range, where the Rocky Mountains meet the Great Plains, the Colorado Office of Emergency Management said.
"We've got a heck of a lot of communities dealing with a heck of a lot of water," Jennifer Finch, a spokeswoman for Weld County north-east of Boulder, told Denver Channel 7 News on Sunday.
On Sunday, traffic on Interstate 25, Colorado's main north-south thoroughfare just east of the mountain range, was brought to a halt by water covering two of the three southbound lanes, according to an AFP correspondent on the road.
The number of people unaccounted for was put as high as 1,253 by the state emergency management office, although Colorado Governor John Hickenlooper put it at 500.
Many of the missing may simply be unable to report their whereabouts, but Mr Hickenlooper warned that the death toll may increase. "There are many, many homes that have been destroyed.
President Barack Obama has declared a major disaster in Colorado and ordered federal aid to support state and local efforts. Hickenlooper called the widespread flooding "a heck of a storm."
Although skies were clearer on Monday, weather forecasters warned that scattered storms could still dump up to an inch of rain in less than 30 minutes, according to KUSA-TV.
Drier, warmer weather conditions are due to return to the battered state on Tuesday, lasting through to Thursday when there is a chance of showers through the region, it said.