Hundreds rescued by National Guard as muddy mountain floods hit Colorado

The inundation since Wednesday has killed four people and turned towns on Colorado's expansive eastern plains into muddy swamps

Efforts to rescue hundreds of people stranded by severe mountain flooding in Colorado have been increased as food and water supplies drop worryingly low and more heavy rain is forecast for today.

National Guard choppers are still evacuating 295 people and their pets from the mountain hamlet of Jamestown, which was rendered cut off by flooding that scoured the canyon the town is situated in.

Governor John Hickenlooper declared a disaster emergency for 14 counties on Friday, reaching from the Wyoming border south to Colorado Springs. The declaration authorizes $6 million in funds to pay for flood response and recovery.

Meanwhile, thousands more residents were forced to abandon their homes as the debris-filled rivers transformed into muddy seas, covering towns and farms miles from the Rockies.

National Guardsmen dropped essential supplies in Jamestown and other small towns in the winding, narrow canyons that dot the Rocky Mountain foothills to those waiting to be airlifted.

Colorado had its first broad view of the destruction caused for the first time since the devastating mountain floods began on Wednesday. The reality of what is becoming a long-term disaster is setting in and flooding has affected parts of a 4,500-square-mile area.

Mike Smith, incident commander at Boulder Municipal Airport, said helicopters would continue flying in and out late into the night.

The outlook for anyone who chooses to remain in the area is weeks without power, mobile phone service, water or sewers.

a raging waterfall destroying a bridge along Highway 34 toward Estes Park (AP)

The rush of water from higher ground has already killed four people and left 172 people still unaccounted for.

The Boulder Office of Emergency Management who listed those unaccounted for following the floods stressed that while they were not yet considered missing or in danger, relatives and authorities had not been able to contact them.

Crews relied on inflatable boats to rescue families and pets from stranded farmhouses. Some evacuees on horseback had to be escorted to safe ground.

It could be months before a semblance of normality returns to Lyons, a gateway community to the park. The town, surrounded by sandstone cliffs whose colour was reflected in the raging St Vrain River, consisted of six islands as residents barbecued their food before it spoiled. Several people set up a tent camp on a hill.

Homes in residential neighborhood in Longmont, Colorado, are submerged (AP)

Additional reporting by Associated Press