Rescuers grounded by weekend rains took advantage of the break in the weather to resume searches for people still stranded, with 21 helicopters fanning out over the mountainsides and the plains to drop supplies and airlift those who need help.
Residents of Hygiene returned to their small community east of the foothills to find mud blanketing roads, garages, even the tops of fence posts. The raging St. Vrain River they fled three days earlier had left trucks in ditches and carried items as far as 2 miles downstream.
"My own slice of heaven, and it's gone," Bill Marquedt said after finding his home destroyed.
Residents immediately set to sweeping, shovelling and rinsing, but the task of rebuilding seemed overwhelming to some.
"What now? We don't even know where to start," said Genevieve Marquez. "It's not even like a day by day or a month thing.
"I want to think that far ahead but it's a minute by minute thing at this point. And, I guess now it's just help everyone out and try to get our lives back," she added.
In the mountain towns, major roads were washed away or covered by mud and rock slides. Hamlets like Glen Haven were reduced to debris and key infrastructure like gas lines and sewers systems were destroyed.
Hundreds of homes around Estes Park, next to Rocky Mountain National Park, could be unreachable and uninhabitable for up to a year, town administrator Frank Lancaster said.
The town of Lyons was almost completely abandoned. Emergency crews gave the few remaining residents, mostly wandering Main Street looking for status updates, a final warning to leave Sunday.
Most of the town's trailer parks were completely destroyed. One angry man was throwing his possessions one by one into the river rushing along one side of his trailer on Sunday, watching the brown water carry them away while drinking a beer.
State emergency officials offered a first glimpse at the scope of the damage, with counties reporting about 19,000 homes either damaged or destroyed.
Those preliminary figures are certain to change as the waters continue to recede and roads are cleared to allow crews to access more areas.
Searchers in the air and on the ground scoured isolated areas from the foothills east to homes and communities along waterways downstream.
Cole Cannon, a volunteer firefighter with the Indian Peaks Fire Protection District, said he encountered mud, rocks, slides and fallen trees rode as he rode an all-terrain vehicle down Lefhand Canyon to the town of Rowena.
Numerous houses had been destroyed, and he didn't know whether the residents had escaped or would be found dead.
"A little bit of both, probably," he said.
The confirmed death toll stood at four, with two women missing and presumed dead.
The number of missing people was difficult to pinpoint, with sometimes conflicting numbers released by state and county officials. At least hundreds were unaccounted for, but he overall number was expected to drop with rescuers reaching more people and phone service being restored.
"You're got to remember, a lot of these folks lost cellphones, landlines, the Internet four to five days ago," Gov. John Hickenlooper said on NBC's "Today" show. "I am very hopeful that the vast majority of these people are safe and sound."
The governor said later at a news conference that many of the bridges, culverts and roadways that were damaged and destroyed were built a long time ago, and with federal assistance, the state could come away with a stronger infrastructure.
"It's not too early to begin planning what the recovery is going to look like," he said.