By Keith Coffman
DENVER (Reuters) - Colorado authorities coping with the aftermath of last week's deadly downpours stepped up the search for victims left stranded in the foothills of the Rockies and evacuations of prairie towns in danger of being swamped as the flood crest moved downstream.
As of Tuesday, eight people were confirmed dead from flash floods triggered by a week of historically heavy rains that drenched a 130-mile (210-km) stretch of the eastern slopes of the Colorado Rockies, with at least 1,600 homes destroyed.
Clusters of towns in the foothills of Larimer and Boulder counties northwest of Denver bore the brunt of the disaster, as floodwaters roared down rain-saturated mountainsides through canyons that funneled the torrent into populated areas below.
The flooding has since progressed downstream and spread out onto the prairie, submerging large tracts of farmland as well as oil and gas well sites in the region as high water rolled eastward toward Nebraska.
The overall flood zone ultimately grew to encompass 17 Colorado counties, including the state's biggest urban centers, across a normally semi-arid region about the size of Delaware.
As the skies finally cleared on Monday, search-and-rescue teams fanned out on foot, in National Guard military vehicles and in helicopters to reach thousands of people cut off in communities isolated by washed-out roads and bridges.
At the same time, emergency management officials in counties further to the east grappled with downstream flooding along the newly engorged South Platte River, which has carried much of the runoff from last week's torrential rains.
Emergency management officials ordered the evacuation early on Tuesday of the tiny riverside town of Crook in northeastern Colorado, where firefighters went door to door asking residents to leave.
High water along the South Platte also forced the closure of every bridge on the river in Logan County, essentially cutting the county in half, officials said. The flood crest was expected to reach the larger riverside town of Julesburg on the Nebraska border on Tuesday afternoon.
LOOKING FOR STRANDED SURVIVORS
Meanwhile, search-and-rescue teams continued to comb through canyon areas hit by flash floods at the height of the disaster, looking for more stranded survivors, said Micki Trost, a spokeswoman for the state Office of Emergency Management.
She said local police and fire personnel as well as search teams from the Federal Emergency Management Agency were taking part in the ground operations.
Nearly 12,000 people have been evacuated to shelters since last week, but at least 1,000 more had yet to be reached on Monday in Larimer County alone.
Trost said the number of people unaccounted for throughout the flood zone had declined to fewer than 500, many of them believed to be merely cut off in remote areas without telephone or Internet service.
In addition to some 1,500 homes destroyed and 4,500 damaged in Larimer County, 200 businesses have been lost and 500 damaged, officials there said. Boulder County officials said more than 100 homes were destroyed in the hard-hit town of Lyons but had no countywide property loss figures.
President Barack Obama declared the area a major disaster over the weekend, freeing up federal funds and resources to aid state and local governments.
Meanwhile, standing water left by the floods was expected to cause significant damage to crops in the predominantly agricultural communities of Morgan County, northeast of Denver.
Oil and natural gas production also was disrupted in the fossil-fuel-rich region of eastern Colorado known as the Denver-Julesburg Basin, with roughly 1,000 wells shut down by flooding, several energy companies reported on Monday.
Local environmental activists have raised concerns about potential leaks of gas, oil and hazardous materials from well sites and other energy facilities compromised by flooding. The Colorado Oil and Gas Conservation Commission said it was working with health authorities to assess environmental impacts.
Last week's downpour, the heaviest to hit the region in four decades, experts said, dumped up to 21 inches of rain in parts of Boulder city, northwest of Denver, nearly double the area's average annual rainfall.
The last multi-day rainfall to spawn widespread flooding in Colorado's Front Range occurred in 1969. But a single-night downpour from a 1976 thunderstorm triggered a flash flood that killed more than 140 people in Big Thompson Canyon.
(Reporting by Keith Coffman; Writing and additional reporting by Steve Gorman; Editing by James Dalgleish)