Chris Schneider/AP
Homeowner Chris Ringdahl, left, is comforted by family friend Katherine MacIntosh, right, in front of her possessions as they cleanup from the floodwaters in Longmont, Colo., Sept. 16, 2013.
Floodwaters have affected a 4,500 square-mile section of the state inundating entire neighborhoods and destroying bridges and roads.
Brennan Linsley/AP
The sun rises over a portion of railroad track undermined by flooding days earlier, in Longmont, Colo., Sept. 17, 2013.
Ed Andrieski/AP
A flood victim is helped off of a helicopter at the Boulder Municipal Airport in Boulder, Colo., Sept. 16, 2013, after being rescued.
Officials hope the number of missing will drop rapidly as communications are restored and people are evacuated throughout the region, as it did in Larimer County, where almost 250 people were lopped off a missing-persons list over the weekend, and Boulder County, where the list shrunk by 187 people.
Chris Schneider/AP
A National Guard truck that was damaged by floodwaters and was carried into a drainage ditch by the current lies next to twisted railroad tracks in Longmont, Colo., Sept. 16, 2013.
Paul Aiken/The Daily Camera/AP
FEMA Urban Search and Rescue Personnel look over a washed out bridge and damaged home in Boulder, Colo., Sept. 16, 2013.
Several homes along the Fourmile Canyon Creek were destroyed or heavily damaged.
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.
Sgt. Jonathan C. Thibault/U.S. Army/AP
A flight medic with the Colorado Air National Guard carries an evacuee up a hoist onto a UH-60 Black Hawk helicopter during flood rescue and recovery operations near Boulder, Colo., Sept. 16, 2013.
Military helicopter crews have flown hundreds of missions up the treacherous canyons of the Rocky Mountains to rescue about 2,000 people, and counting, and drop food and water supplies to stranded hamlets.
Brennan Linsley/AP
Local man Joey Schendel, 19, looks for submerged items while helping neighbors salvage and clean their property in an area inundated after days of flooding in Hygiene, Colo., Sept. 16, 2013.
Brennan Linsley/AP
Local resident Sue Sadar walks across a muddy trench, which used to be a lawn, as she and family members clean property in an area inundated by flooding in Hygiene, Colo., Sept. 16, 2013.
Brennan Linsley/AP
Flood evacuee, 18-month-old Jourleni, plays on her inflatable crib, as her father Rafael Ruiz, left, and mother Evelyn Trevino, center, talk with Maria Hauser, a staffer at the Lifebridge Christian Church in Longmont, Colo., Sept. 16, 2013.
The church has been converted to a shelter for those made homeless by flooding. Jourleni and her parents' home in nearby Lyons, Colo., was destroyed in a flash flood several days earlier.
Brennan Linsley/AP
Local residents, left to right, Levi Wolfe, Miranda Woodard, Tyler Sadar, and Genevieve Marquez help salvage and clean property in an area inundated after days of flooding in Hygiene, Colo., Sept. 16, 2013.
Chris Schneider/AP
A building is surrounded by floodwaters in Loveland, Colo., Sept. 16, 2013.
Brennan Linsley/AP
Water flows through an evacuated neighborhood after days of flooding in Hygiene, Colo., Sept. 15, 2013. After somewhat abating for two days, rain returned to Colorado Sunday, creating a risk of more flooding and mudslides.
Four people are confirmed dead and two more are missing and presumed dead. Some 1,500 homes have been destroyed and about 17,500 have been
damaged, according to an initial estimate by the Colorado Office of Emergency Management.
Marc Piscotty/Getty Images
Local residents take in a closeup view of a damaged bridge on Weld County Road 1, Sept. 13, 2013, in Longmont, Colorado. Heavy rains for the better part of week have fueled widespread flooding in numerous Colorado towns.
Brennan Linsley/AP
Water flows through an evacuated neighborhood after days of flooding in Hygeine, Colo., Sept. 15, 2013.
Marc Piscotty/Getty Images
Debris gathers in front of a home in La Salle, Colo., Sept. 14, 2013. The historic flooding forced thousands to evacuate the area.
Marc Piscotty/Getty Images
Water rushes down a flooded Topaz Street on Sept. 13, 2013 in Boulder, Colo. Heavy rains for the better part of week have fueled widespread flooding and evacuations in numerous Colorado towns, with the area reportedly already having received 15 inches of rain.
Dawn Madura/The Coloradoan/AP
Johnny Heginbootom looks out across his backyard, where a 10-foot fence is partially submerged on Sunday, Sept. 15, 2013, in Laporte, Colo. Heginbootom rents the home and on Sunday he and the home owners were working on pumping out water and removing soaked flooring.
Jeremy Papasso/Daily Camera/AP
A pile of flooded belongings sits in a driveway on Iris Avenue in Boulder, Colo., Sept. 15, 2013. Colorado emergency management officials have released an initial estimate that says the ongoing flooding has damaged or destroyed nearly 19,000 homes.
John Wark/AP
A field of parked cars and trucks sits partially submerged near Greeley, Colo., Sept. 14, 2013, as debris-filled rivers flooded into towns and farms miles from the Rockies.
Jeremy Papasso/Daily Camera/AP
Lefthand Canyon Road near the intersection of Olde Stage Road in Boulder, Colo., Sept. 14, 2013.
Jeremy Papasso/Daily Camera/AP
Lefthand Canyon Drive is in ruins on Olde Stage Road in Boulder, Colo., Sept. 14, 2013. Rescuers rushed by land and by air Saturday to evacuate Coloradoans stranded by epic mountain flooding as debris-filled rivers became muddy seas that extended into towns and farms miles from the Rockies.
John Wark/AP
A group of trailers are smashed together at a storage site near Greeley, Colo., Sept. 14, 2013, as debris-filled rivers flooded into towns and farms miles from the Rockies. Hundreds of roads, farms and businesses in the area have been damaged or destroyed by the floodwaters.
John Wark/AP
A section of highway is washed out by flooding along the South Platte River in Weld County, Colorado near Greeley, Sept. 14, 2013.
John Wark/AP
A tractor sits partially submerged in a field after flooding along the South Platte River in Weld County, Colo., Sept. 14, 2013.
Brennan Linsley/AP
Flood evacuees and loved ones talk at a drop-off point for those rescued after days of flooding, at a high school in Niwot, Colo., Sept. 14, 2013.
John Wark/AP
People stand at the edge of a highway washed out by flooding along the South Platte River in Weld County, Colo., Sept. 14, 2013.
Matthew Kennedy/AP/Courtesy Earth Vision Trust
Destruction on Gold Run Creek north of Boulder, Colo., Sept. 13, 2013.
Dennis Pierce/Colorado Heli-Ops/AP
Homes in Lyons, Colo. are surrounded by water as flooding continues to devastate the Front Range, forcing thousands to evacuate, with an unconfirmed number of structures destroyed, Sept. 13, 2013.
John Wark/AP
A residential neighborhood and a connecting road in Lyons, Colo., are separated by flood waters as flooding continues to devastate the Front Range Friday, Sept. 13, 2013.
Jeremy Papasso/Daily Camera/AP
Brian Montgomery helps his mother Barbara Yanari to clean up the mud in her flooded basement on Olde Stage Road in Boulder, Colo, Sept. 14, 2013.
John Wark/AP
Homes in Longmont, Colo., are submerged as flooding continues to devastate the Front Range and thousands are forced to evacuate with an unconfirmed number of structures destroyed, Sept. 13, 2013.
Brennan Linsley/AP
The overflowing St. Vrain River swamps a structure and a piece of heavy machinery following overnight flash flooding, one mile east of Lyons, Colo., Sept. 12, 2013.
Cliff Grassmick/The Daily Camera/AP
A man photographs floodwater in the underpass at Boulder Creek and Broadway Street in Boulder, Colo., Sept. 12, 2013.
Brennan Linsley/AP
A man walks past dangerously high Boulder Creek following overnight flash flooding in downtown Boulder, Colo., Sept. 12, 2013.
The Boulder Office of Emergency Management said debris and mud coming off the mountainsides caused water to back up at the mouth of the Boulder Canyon, resulting in the creek's rapid rise.
Ben Neary/AP
Residents of a neighborhood on the northern side of Boulder, Colo., work to divert floodwaters away from their homes, Sept. 12, 2013.
Jud Valeski/AP
Floodwaters course through a small park in Boulder, Colo., Sept. 12, 2013.
Brennan Linsley/AP
Local residents look over a road washed out by a torrent of water following overnight flash flooding near Left Hand Canyon, south of Lyons, Colo., Sept 12, 2013. The widespread high waters kept search and rescue teams from reaching stranded residents in Lyons and nearby mountain communities as heavy rains hammered northern Colorado.
"There's no way out of town. There's no way into town. So, basically, now we're just on an island," said Lyons resident Jason Stillman.
Brennan Linsley/AP
A road is washed out by a torrent of water following overnight flash flooding near Left Hand Canyon, south of Lyons, Colo., Sept 12, 2013.
CBS News
A roadway in Lafayette, Colo., collapsed, sending three vehicles into the water. Emergency crews managed to rescue the three drivers.
CBS News
Emergency workers rescue a man trapped inside a car that was submerged upside-down in flood waters in Lafayette, Colo., after a roadway collapsed due to massive flooding.
Peter M. Fredin/AP
Paul and Jean Snyder wade through a foot of water flooding their rural Erie, Colo. property on Thursday, Sept. 12, 2013.
Brennan Linsley/AP
Rescue workers and vehicles stand parked waiting for roads to become passable following overnight flash flooding in Boulder, Colo., Sept 12, 2013.
Brennan Linsley/AP
The overflowing St. Vrain River swamps structures following overnight flash flooding, one mile east of Lyons, Colo., Sept. 12, 2013.
Michael Ciaglo/The Colorado Springs Gazette/AP
Floodwater shoots out of a sewer on Canon Avenue in Manitou Springs, Colo., Sept. 12, 2013.
Dana Romanoff/Getty Images
A woman looks at Boulder Creek, which flooded early today after three days of heavy rainfall in Boulder, Colo., Sept. 12, 2013.
Brennan Linsley/AP
Debris floats down the overflowing St. Vrain River following overnight flash flooding, one mile east of Lyons, Colo., Sept. 12, 2013.
Brennan Linsley/AP
Firefighters keep watch over a road washed out by a torrent of water following overnight flash flooding near Left Hand Canyon, south of Lyons, Colo., Sept. 12, 2013.
Brennan Linsley/AP
A car drives on a flooded road following overnight flash flooding in downtown Boulder, Colo., Sept. 12, 2013.
Ed Andrieski/AP
Brian Flynn, of Oregon, clears a drain in front of his sister's home in Boulder, Colo., Sept. 12, 2013.
Brennan Linsley/AP
A torrent of water rushes alongside a swamped house following flash flooding near Left Hand Canyon, south of Lyons, Colo., Sept. 12, 2013.
Dana Romanoff/Getty Images
Motorists attempt to drive through downtown Boulder, Colo. after three days of heavy rainfall Sept. 12, 2013. An estimated 6-10 inches of rain fell in 12-18 hours.
Dana Romanoff/Getty Images
Nicky Toor, 15, is pulled by his dog Chaco down Ninth Street alongside North Boulder Park in Boulder, Colo., Sept. 12, 2013.
AP Photo/Ed Andrieski
A duck swims near bleachers at Utah Park in Aurora, Colo., Sept. 12, 2013.
AP/Earth Vision Trust
Destruction on Gold Run Creek north of Boulder, Colo., is seen in the aftermath of flooding in the area, Sept. 13, 2013.
CBS News
The Colorado National Guard is working non-stop to airlift stranded residents cut off from the rest of the state after record flooding washes out roads. Floodwaters have spread from the foothills to the eastern plains.