DENVER — A summer that began with ferocious wildfires ended with disastrous floods in Colorado as a late burst of rain Sunday hampered rescue efforts and fueled flash-flood warnings in waterlogged communities.
An estimated 1,250 people were unaccounted for after five days of heavy rain flooded highways, collapsed bridges and engulfed houses along Colorado’s Front Range and foothills. The death toll rose to six after a woman’s house was swept away by flooding.
The National Guard rescued 2,100 people Saturday, 700 by air, but rain forced responders to limit the search Sunday. Sixteen helicopters sat on the tarmac at Boulder Municipal Airport on Sunday, grounded by the clouds that were expected to bring an additional 1 to 3 inches of rain.
“It will affect our air operations if it keeps raining,” Colorado National Guard Lt. James Goff said. “We’ll look at ground operations of any other courses of action.”
President Obama declared a major disaster declaration Sunday for Colorado, approving federal aid for recovery efforts in Boulder, El Paso and Larimer counties, three of the hardest hit, but by no means only, communities affected by the unprecedented September rainfall.
Fifteen counties stretching across 200 miles along the eastern edge of the Rocky Mountains are struggling with flooding. Another round of evacuations was ordered Sunday in Boulder, Logan and Weld counties, as well as in some foothills towns, bringing to the number of people evacuated to 11,700, according to Colorado Emergency Management.
Colorado Gov. John Hickenlooper said most of the people missing are likely unable to communicate with their families but not in immediate danger.
“There are still more people that we haven’t found, who are not in peril for their lives, they’ve still got food, but they obviously have been three, four days without power, without cellphones, without Internet connections,” Mr. Hickenlooper said on CNN’s “State of the Union.”
“So they’re pretty frustrated, and probably a little bit anxious, in many cases very anxious,” he said. “So we’re trying to find them. Unfortunately, the cloud cover today is going to make it difficult to do helicopter search-and-rescue.”
The governor said he has been in touch with Vermont Gov. Peter Shumlin to discuss disaster recovery. The state was lauded for its rapid rebound after it was hit in 2011 by Hurricane Irene.
The Colorado Transportation Department reported that 30 bridges have been destroyed and damage has not been assessed on several roads.
“We’ve got a lot of broken roads and broken bridges, but we don’t have any broken spirits,” Mr. Hickenlooper said.
The sixth victim is believed to be an 80-year-old woman in Larimer County whose home was washed away in the flooding along the Big Thompson River. She lived in the Cedar Cove area, where another woman is believed to have died when her home was flooded.
Nearly 2,000 people were taking refuge in 26 shelters, and their stories began to trickle out Sunday. Emma Hardy of Jamestown said her husband woke her Wednesday night to tell her that a neighbor had been killed by a mudslide that destroyed his home.
The couple began knocking on doors to warn neighbors, but a river soon formed that split the town.