The rescue of hundreds of Coloradoans stranded by epic mountain flooding was accelerating as food and water supplies ran low, while thousands more were driven from their homes on the plains as debris-filled rivers became muddy seas inundating towns and farms miles from the Rockies.

For the first time since the harrowing mountain floods began Wednesday, Colorado got its first broad view of the devastation _ and the reality of what is becoming a long-term disaster is setting in. The flooding has affected parts of a 4,500-square-mile (11,655-sq. kilometer) area.

National Guard choppers were evacuating 295 people _ plus pets _ from the mountain hamlet of Jamestown, which was isolated by flooding that scoured the canyon the town sits in.

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'd rather stay is weeks without power, cellphone service, water or sewer.

For those awaiting an airlift, Guardsmen dropped food, water and other supplies in Jamestown and other small towns in the winding, narrow canyons that dot the Rocky Mountain foothills.

Thousands of evacuees sought shelter in cities that were nearly surrounded by raging rivers spilling over their banks.

The dayslong rush of water from higher ground has killed four people and turned towns on Colorado's expansive eastern plains into muddy swamps. Crews used inflatable boats to rescue families and pets from stranded farmhouses. Some evacuees on horseback had to be escorted to safe ground.

Boulder County officials said Friday night that the number of people unaccounted for had risen to 172, according to local television and newspaper reports. The officials said earlier that the unaccounted for figure doesn't necessarily represent missing people.

It will be weeks, if not months, before a semblance of normalcy returns to Lyons, a gateway community to the park. The town, surrounded by sandstone cliffs whose color was reflected in the raging St. Vrain River, consisted of six islands Friday as residents barbecued their food before it spoiled. Several people set up a tent camp on a hill.

Some 2,500 residents were being evacuated from Lyons, but Hilary Clark was left walking around her neighborhood Friday.

Two bridges that led into the area were washed away. Unlike other parts of Lyons that had been reached by the National Guard in high clearance trucks, no such help had arrived for Clark. (AP)