It continued to rain in Colorado Sunday, sending more water rushing down already-swollen streams, threatening more homes and business, and making search and rescue efforts difficult. Officials say some rivers could continue to flood until Tuesday.
Four people are confirmed dead and two more are presumed lost after their homes washed away.
Hundreds more were unaccounted for, although that number was expect to drop as telephone service was restored.
Flash flood warnings were in place in all or portions of the following counties: Adams, Arapahoe, Boulder, Broomfield and Denver, reports the Denver Post. All of northeast Colorado remains under a flood warning.
"The situation has deteriorated since early this morning," Andrew Barth, spokesman for Boulder County Emergency Management, told the newspaper. "There's a heavy, heavy fog and rain is coming down hard. Standing water is rising because the ground is saturated."
On Sunday, fog grounded the helicopters that had evacuated about 1,500 people Saturday.
"Residents should prepare to evacuate for what may be an extended period of time, as road and infrastructure repairs could take several months," according to a news release from officials in the community of Estes Park, the gateway to Rocky Mountain National Park. "Residents must understand that with winter weather impending, staying at home in this area is an extremely dangerous decision and emergency services will not be available to them after evacuation.
Boulder remained a refuge for evacuees from the more isolated mountain towns. These refugees filled a church, a YMCA and a high school and crashed on couches around town. Meanwhile, water continued to back up in some parts of town and a water treatment plant remained down Sunday.
But the town was bouncing back. Libraries and recreation centers have reopened, and classes at the University of Colorado are expected to resume Monday.
President Obama has declared a major disaster in Colorado, authorizing Federal funds for flood victims.
Assistance can include grants for temporary housing and home repairs, low-cost loans to cover uninsured property losses, and other programs to help individuals and business owners recover from the effects of the disaster, according to a White House statement. Federal funding also is available to state and eligible local governments and certain private nonprofit organizations on a cost-sharing basis for emergency work in Boulder County.
Federal Emergency Management Agency administrator Craig Fugate will travel to Colorado Monday to help coordinate a federal response.
Three federal urban search and rescue teams are on the ground to support search and rescue operations in flooded and isolated areas, the White House reported Sunday. Two additional federal urban search and rescue teams were expected to arrive in Colorado Sunday afternoon, and three more federal urban search and rescue teams have been placed on alert.
Meanwhile, in the neighboring state of New Mexico, another round of rain moved across the state on Sunday, renewing the threat of heavy runoff from already saturated soils and flooding in low areas as residents faced a major cleanup effort from damage left in the wake of days of relentless rain.
The National Weather Service issued a flash flood watch for much of central and northern New Mexico. The flooding killed at least one person – a man whose car was washed into a ravine and carried nearly a mile from the road.
This report includes material from the Associated Press.